Seven piece set, 3/8" square drive. High strength, heat-treated alloy steel bits, with black oxide finish, are securely broached into plated sockets. No set screws to tighten! Bit sets store in a convenient vinyl storage holder. Sizes: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm and 10mm. Made in Clarinda, IA, U.S.A.