{"title":"21*17 SEF Coils","description":"\u003cp\u003eFind all compatible 21×17\" (53×43 cm) SEF search coils for your metal detector. Select the coil only for your specific detector model to ensure proper fit and wiring. Free EU shipping, invoice \u0026amp; warranty included.\u003c\/p\u003e","products":[{"product_id":"21-17-for-minelab-sd-gp-gpx","title":"21*17 for Minelab SD \/ GP \/ GPX","description":"\u003ch2 data-section-id=\"1p8w332\" data-start=\"220\" data-end=\"298\"\u003eDetech 21×17\" S.E.F Butterfly Search Coil for Minelab and White’s Detectors\u003c\/h2\u003e\n\u003cp data-start=\"300\" data-end=\"617\"\u003eEnhance your treasure hunting with the \u003cstrong data-start=\"339\" data-end=\"388\"\u003eDetech 21×17 inch S.E.F Butterfly search coil\u003c\/strong\u003e, specially designed for \u003cstrong data-start=\"413\" data-end=\"447\"\u003eMinelab SD, GP, and GPX series\u003c\/strong\u003e as well as \u003cstrong data-start=\"459\" data-end=\"481\"\u003eWhite’s TDI models\u003c\/strong\u003e. This is the \u003cstrong data-start=\"495\" data-end=\"534\"\u003elargest DD coil in the S.E.F series\u003c\/strong\u003e, delivering \u003cstrong data-start=\"547\" data-end=\"614\"\u003eunmatched depth, sensitivity, and precise target identification\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch3 data-section-id=\"16c2ni1\" data-start=\"619\" data-end=\"653\"\u003eUnmatched Sensitivity for Gold\u003c\/h3\u003e\n\u003cp data-start=\"655\" data-end=\"898\"\u003eExperience extreme depth and sensitivity with this lightweight, high-performance coil. Ideal for detecting elusive nuggets, relics, and deep targets, it’s perfect for historical battlefields, gold-rich terrains, and challenging environments.\u003c\/p\u003e\n\u003ch3 data-section-id=\"1vdj73a\" data-start=\"900\" data-end=\"928\"\u003eDesigned for Great Depth\u003c\/h3\u003e\n\u003cp data-start=\"930\" data-end=\"1155\"\u003eThe \u003cstrong data-start=\"934\" data-end=\"959\"\u003e21×17 inch S.E.F coil\u003c\/strong\u003e goes deeper than any other in the series, making it the ultimate choice for finding gold at significant depths. Combine it with your Minelab GPX detector or White’s TDI for maximum performance.\u003c\/p\u003e\n\u003ch3 data-section-id=\"r8ylsb\" data-start=\"1157\" data-end=\"1182\"\u003ePrecision Pinpointing\u003c\/h3\u003e\n\u003cp data-start=\"1184\" data-end=\"1364\"\u003eBenefit from \u003cstrong data-start=\"1197\" data-end=\"1221\"\u003eaccurate pinpointing\u003c\/strong\u003e to reduce unnecessary digging and improve target detection. Every beep could lead to a valuable find, giving you confidence in every search.\u003c\/p\u003e\n\u003ch3 data-section-id=\"1f7yu0a\" data-start=\"1366\" data-end=\"1382\"\u003eTop Features\u003c\/h3\u003e\n\u003cul data-start=\"1384\" data-end=\"1700\"\u003e\n\u003cli data-section-id=\"1shm2l\" data-start=\"1384\" data-end=\"1416\"\u003e\n\u003cp data-start=\"1386\" data-end=\"1416\"\u003e\u003cstrong data-start=\"1386\" data-end=\"1400\"\u003eCoil Type:\u003c\/strong\u003e DD \/ Double D\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"wv5gt3\" data-start=\"1417\" data-end=\"1439\"\u003e\n\u003cp data-start=\"1419\" data-end=\"1439\"\u003e\u003cstrong data-start=\"1419\" data-end=\"1429\"\u003eShape:\u003c\/strong\u003e Ellipse\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"vbdz5z\" data-start=\"1440\" data-end=\"1460\"\u003e\n\u003cp data-start=\"1442\" data-end=\"1460\"\u003e\u003cstrong data-start=\"1442\" data-end=\"1451\"\u003eSize:\u003c\/strong\u003e 21×17\"\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"10lesqv\" data-start=\"1461\" data-end=\"1537\"\u003e\n\u003cp data-start=\"1463\" data-end=\"1537\"\u003e\u003cstrong data-start=\"1463\" data-end=\"1481\"\u003eConfiguration:\u003c\/strong\u003e S.E.F (Symmetrical Electromagnetic Field) – Butterfly\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"13z1ny9\" data-start=\"1538\" data-end=\"1567\"\u003e\n\u003cp data-start=\"1540\" data-end=\"1567\"\u003e\u003cstrong data-start=\"1540\" data-end=\"1551\"\u003eWeight:\u003c\/strong\u003e Approx. 907 g\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"5nnng3\" data-start=\"1568\" data-end=\"1622\"\u003e\n\u003cp data-start=\"1570\" data-end=\"1622\"\u003e\u003cstrong data-start=\"1570\" data-end=\"1599\"\u003eEnhanced ground balancing\u003c\/strong\u003e and stable operation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"1hz2qzw\" data-start=\"1623\" data-end=\"1665\"\u003e\n\u003cp data-start=\"1625\" data-end=\"1665\"\u003e\u003cstrong data-start=\"1625\" data-end=\"1648\"\u003eCoil cover included\u003c\/strong\u003e for protection\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"1fe590q\" data-start=\"1666\" data-end=\"1700\"\u003e\n\u003cp data-start=\"1668\" data-end=\"1700\"\u003e\u003cstrong data-start=\"1668\" data-end=\"1689\"\u003eTwo-year warranty\u003c\/strong\u003e included\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 data-section-id=\"purqi0\" data-start=\"1702\" data-end=\"1719\"\u003eCompatibility\u003c\/h3\u003e\n\u003cp data-start=\"1721\" data-end=\"1886\"\u003e\u003cstrong data-start=\"1721\" data-end=\"1733\"\u003eMinelab:\u003c\/strong\u003e GP3000, GP 3500, GP Extreme, GPX 4000, GPX 4500, GPX 4800, GPX 5000, SD2000, SD2100, SD2100 V2, SD2200D, SD2200D V2\u003cbr data-start=\"1849\" data-end=\"1852\"\u003e\u003cstrong data-start=\"1852\" data-end=\"1864\"\u003eWhite’s:\u003c\/strong\u003e TDI, TDI Pro, TDI S\u003c\/p\u003e\n\u003cp data-start=\"1888\" data-end=\"2130\"\u003eTake your detecting to the next level with the \u003cstrong data-start=\"1935\" data-end=\"1973\"\u003eDetech 21×17\" S.E.F Butterfly coil\u003c\/strong\u003e – engineered for \u003cstrong data-start=\"1991\" data-end=\"2056\"\u003emaximum depth, superior sensitivity, and reliable performance\u003c\/strong\u003e. Perfect for serious hobbyists and professional treasure hunters alike.\u003c\/p\u003e","brand":"Detech","offers":[{"title":"Default Title","offer_id":53965257998676,"sku":null,"price":224.99,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1018\/5218\/4916\/files\/21x17-dd-gpx.jpg?v=1773825955"},{"product_id":"minelab-21-17","title":"Minelab and Detech 21*17 SEF coil","description":"\u003ch3 data-section-id=\"152n1qe\" data-start=\"442\" data-end=\"488\"\u003eDetech 21x17\" SEF Butterfly DD Search Coil\u003c\/h3\u003e\n\u003cp data-start=\"490\" data-end=\"777\"\u003eThe Detech 21x17\" SEF (Symmetrical Electromagnetic Field) Butterfly DD Search Coil is designed for maximum depth and superior performance in all terrains. This large elliptical coil provides exceptional ground coverage while maintaining excellent stability and accurate target detection.\u003c\/p\u003e\n\u003cp data-start=\"779\" data-end=\"985\"\u003eBuilt with patented SEF (Butterfly) technology, this coil delivers enhanced sensitivity and improved depth compared to standard DD coils, making it ideal for serious detectorists searching for deep targets.\u003c\/p\u003e\n\u003chr data-start=\"987\" data-end=\"990\"\u003e\n\u003ch3 data-section-id=\"oc6kxx\" data-start=\"992\" data-end=\"1015\"\u003eKey Specifications:\u003c\/h3\u003e\n\u003cul data-start=\"1017\" data-end=\"1254\"\u003e\n\u003cli data-section-id=\"d356b\" data-start=\"1017\" data-end=\"1045\"\u003eCoil Type: DD (Double D)\u003c\/li\u003e\n\u003cli data-section-id=\"31vz01\" data-start=\"1046\" data-end=\"1113\"\u003eTechnology: SEF (Symmetrical Electromagnetic Field) – Butterfly\u003c\/li\u003e\n\u003cli data-section-id=\"toe2la\" data-start=\"1114\" data-end=\"1151\"\u003eSize: 21 x 17 inches (elliptical)\u003c\/li\u003e\n\u003cli data-section-id=\"yghych\" data-start=\"1152\" data-end=\"1177\"\u003eWeight: approx. 907 g\u003c\/li\u003e\n\u003cli data-section-id=\"9zdg6c\" data-start=\"1178\" data-end=\"1205\"\u003eWaterproof construction\u003c\/li\u003e\n\u003cli data-section-id=\"1ohe4g\" data-start=\"1206\" data-end=\"1230\"\u003eUV protected housing\u003c\/li\u003e\n\u003cli data-section-id=\"196jbec\" data-start=\"1231\" data-end=\"1254\"\u003eCoil cover included\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"1256\" data-end=\"1259\"\u003e\n\u003ch3 data-section-id=\"u2ms2\" data-start=\"1261\" data-end=\"1279\"\u003eCompatibility:\u003c\/h3\u003e\n\u003cp data-start=\"1281\" data-end=\"1324\"\u003eThis Detech search coil is compatible with:\u003c\/p\u003e\n\u003cul data-start=\"1326\" data-end=\"1492\"\u003e\n\u003cli data-section-id=\"3d7quw\" data-start=\"1326\" data-end=\"1353\"\u003eMinelab Explorer series\u003c\/li\u003e\n\u003cli data-section-id=\"118mr50\" data-start=\"1354\" data-end=\"1372\"\u003eMinelab E-Trac\u003c\/li\u003e\n\u003cli data-section-id=\"hdojdy\" data-start=\"1373\" data-end=\"1391\"\u003eMinelab Safari\u003c\/li\u003e\n\u003cli data-section-id=\"r7vikw\" data-start=\"1392\" data-end=\"1411\"\u003eMinelab Quattro\u003c\/li\u003e\n\u003cli data-section-id=\"1e1d16b\" data-start=\"1412\" data-end=\"1467\"\u003eMinelab Sovereign XS \/ XS-2 \/ XS-2A \/ XS Elite \/ GT\u003c\/li\u003e\n\u003cli data-section-id=\"46m6si\" data-start=\"1468\" data-end=\"1492\"\u003eDetech Relic Striker\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"1494\" data-end=\"1497\"\u003e\n\u003ch3 data-section-id=\"q4c1cr\" data-start=\"1499\" data-end=\"1512\"\u003eFeatures:\u003c\/h3\u003e\n\u003cul data-start=\"1514\" data-end=\"1976\"\u003e\n\u003cli data-section-id=\"1mvhvaw\" data-start=\"1514\" data-end=\"1566\"\u003ePatented SEF technology for improved performance\u003c\/li\u003e\n\u003cli data-section-id=\"1op7op9\" data-start=\"1567\" data-end=\"1619\"\u003eDesigned for increased depth and ground coverage\u003c\/li\u003e\n\u003cli data-section-id=\"w9cwan\" data-start=\"1620\" data-end=\"1661\"\u003eStable operation in mineralized soils\u003c\/li\u003e\n\u003cli data-section-id=\"60kysm\" data-start=\"1662\" data-end=\"1698\"\u003eHigh sensitivity to deep targets\u003c\/li\u003e\n\u003cli data-section-id=\"k7w8ws\" data-start=\"1699\" data-end=\"1749\"\u003eReinforced ribbed housing for shock absorption\u003c\/li\u003e\n\u003cli data-section-id=\"1xeov7g\" data-start=\"1750\" data-end=\"1824\"\u003eManufactured using high-quality polymer with glass fiber reinforcement\u003c\/li\u003e\n\u003cli data-section-id=\"1mb6d90\" data-start=\"1825\" data-end=\"1887\"\u003eAdvanced electromagnetic shielding for minimal signal loss\u003c\/li\u003e\n\u003cli data-section-id=\"14ndn5s\" data-start=\"1888\" data-end=\"1919\"\u003eWaterproof and UV resistant\u003c\/li\u003e\n\u003cli data-section-id=\"ztviqi\" data-start=\"1920\" data-end=\"1976\"\u003eReliable performance across a wide temperature range\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"1978\" data-end=\"1981\"\u003e\n\u003ch3 data-section-id=\"1570i2o\" data-start=\"1983\" data-end=\"2008\"\u003ePerformance Benefits:\u003c\/h3\u003e\n\u003cul data-start=\"2010\" data-end=\"2318\"\u003e\n\u003cli data-section-id=\"lf8cqb\" data-start=\"2010\" data-end=\"2075\"\u003eUp to 10–15% increased depth (depending on ground conditions)\u003c\/li\u003e\n\u003cli data-section-id=\"103fqut\" data-start=\"2076\" data-end=\"2103\"\u003eImproved ground balance\u003c\/li\u003e\n\u003cli data-section-id=\"faralo\" data-start=\"2104\" data-end=\"2151\"\u003eMore stable operation in difficult terrains\u003c\/li\u003e\n\u003cli data-section-id=\"9xtu7m\" data-start=\"2152\" data-end=\"2196\"\u003eEnhanced sensitivity and target response\u003c\/li\u003e\n\u003cli data-section-id=\"cvhxyo\" data-start=\"2197\" data-end=\"2236\"\u003eMore accurate target identification\u003c\/li\u003e\n\u003cli data-section-id=\"1bxiyut\" data-start=\"2237\" data-end=\"2281\"\u003eExcellent pinpointing despite large size\u003c\/li\u003e\n\u003cli data-section-id=\"1wmws6l\" data-start=\"2282\" data-end=\"2318\"\u003eBetter overall field performance\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2320\" data-end=\"2323\"\u003e\n\u003ch3 data-section-id=\"1wabczm\" data-start=\"2325\" data-end=\"2342\"\u003eIntended Use:\u003c\/h3\u003e\n\u003cul data-start=\"2344\" data-end=\"2493\"\u003e\n\u003cli data-section-id=\"1mdh7zk\" data-start=\"2344\" data-end=\"2365\"\u003eDeep coin hunting\u003c\/li\u003e\n\u003cli data-section-id=\"qakycr\" data-start=\"2366\" data-end=\"2396\"\u003eRelic and artifact hunting\u003c\/li\u003e\n\u003cli data-section-id=\"imn8zw\" data-start=\"2397\" data-end=\"2420\"\u003eLarge area coverage\u003c\/li\u003e\n\u003cli data-section-id=\"1lmpy49\" data-start=\"2421\" data-end=\"2445\"\u003eOpen field detecting\u003c\/li\u003e\n\u003cli data-section-id=\"1269q7b\" data-start=\"2446\" data-end=\"2493\"\u003eUse in mineralized and challenging terrains\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2495\" data-end=\"2498\"\u003e\n\u003ch3 data-section-id=\"7avop4\" data-start=\"2500\" data-end=\"2513\"\u003eWarranty:\u003c\/h3\u003e\n\u003cul data-start=\"2515\" data-end=\"2547\"\u003e\n\u003cli data-section-id=\"19nyp3v\" data-start=\"2515\" data-end=\"2547\"\u003e2-year manufacturer warranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2549\" data-end=\"2552\"\u003e\n\u003ch3 data-section-id=\"1whgrsd\" data-start=\"2554\" data-end=\"2579\"\u003eWhy Choose This Coil?\u003c\/h3\u003e\n\u003cp data-start=\"2581\" data-end=\"2862\"\u003eThe Detech 21x17\" SEF Butterfly coil is built for maximum depth and efficiency. It is the perfect upgrade for detectorists who want to cover large areas quickly while still achieving deep and accurate target detection. Ideal for open terrains where depth and coverage are critical.\u003c\/p\u003e","brand":"Detech","offers":[{"title":"Default Title","offer_id":54074585252180,"sku":null,"price":165.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1018\/5218\/4916\/files\/21-17-coils_c3a80f29-7644-4cfe-9cf4-17b006c6d631.webp?v=1775025706"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1018\/5218\/4916\/collections\/21-17-coils.webp?v=1773745556","url":"https:\/\/detnix.com\/en-us\/collections\/21-17-sef-coils.oembed","provider":"Detnix","version":"1.0","type":"link"}