Butterfly Metal Detector Search Coils

About

Butterfly coils, best known through Detech's SEF (Symmetrical Electromagnetic Field) series, set two D-shaped windings tip to tip so the coil flares wide at the ends and narrows at the waist. The layout sweeps a wider strip of ground per pass than a round coil of similar weight while holding depth on larger targets, which is why relic hunters covering big fields keep reaching for it. Quick links: All Search Coils | Round | Elliptical | Semi-Elliptical