3/8", internal square drive, super flat, 18-piece, wrench size 8-22mm, full steel reversible ratchet with clockwise and counter-clockwise operation, ergonomically shaped handle, socket wrench inserts without lead-in chamfer. Super short inserts allow working in very tight spaces and direct attachment to the nut or screw connection. Drive type / profile external hexagon drive 3/8" type article features reversible main color silver wrench size 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 21 mm, 22 mm assortment 18 pieces