Based in Bulgaria, Detech provides one of the most revolutionary types of coils on the market – S.E.F. (Symmetrical Electromegnetic Field) coils, known also as Butterfly coils. These searchcoils combine the advantages of both DD and Concentric coils.  The S.E.F. Butterfly search coils offer better ground balance, more stable operation in all conditions, even deeper in the ground, and more accurate target identification