This set allows you to mix and match drive sizes for your sockets, ratchet handles, extension bars and other accessories.1/2" to 3/8" - (12.5mm square hole to 9.5mm square head) Length: 36mm3/8" to 1/4" - (9.5mm square hole to 6.3mm square head) Length: 26mm 3/8" to 1/2" - (9.5mm square hole to 12.5mm square head) Length: 35mm1/4" to 3/8" - (6.3mm square hole to 9.5mm square head) Length: 25mmSpecification:This set allows you to mix and match drive sizes for your sockets, ratchet handles, extension bars and other accessories.Made of high quality chrome vanadium, CRV alloy, high quality, durable Full tempered heat treatment, high hardness, chrome surfaceIdeal tool for mechanics, engineers, carpenters or DIYersSprung Ball Bearing< p>Specification:Hardness: 60HRCHeight: about 25mm, 26mm, 35mm, 36mmMain material: Chrome vanadium steelSurface treatment: black electrophoresisSize:1/2" to 3/8" - (hole 12.5mm square to 9.5mm square head) Length: 36mm3/8" to 1/4" - (9.5mm square hole to 6.3mm square head) Length: 26mm3/8" to 1/2" - (9.5mm square hole to 12.5mm square head) Length: 35mm1/4" to 3/8" - (hole 6.3mm square to 9.5mm square head) Length: 25mmContneu:4pcs Increaser and Reducer Adapters