General description This 4-piece adapter set allows you to mix and match drive sizes for your sockets, ratchet handles, extension bars, and other accessories. Technical specifications 1/2" to 3/8" - Square hole of 12.5mm to square head of 9.5mm, Length: 36mm 3/8" to 1/4" - Square hole of 9.5mm to square head of 6.3mm, Length: 26mm 3/8" to 1/2" - Square hole of 9.5mm to square head of 12.5mm, Length: 35mm 1/4" to 3/8" - Square hole of 6.3mm to square head of 9.5mm, Length: 25mm