These Faithfull Hexagon Sockets are professional, high quality 3/8in drive metric sockets forged from chrome vanadium steel, which is hardened, tempered and satin chrome plated for corrosion protection. Faithfull sockets have a hexagon design that gives an accurate fit on both nuts and bolts and the chamfered end allows easy nut location and entry.The FAISOC3819 Hexagon Socket has the following specifications: Drive: 3/8 inch square. Size: 19mm Hexagon.