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: 36mm 3/8 "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: 35mm 1/4 "to 3/8" - (6.3mm square hole to 9.5mm square head) Length: 25 mm Specification: Hardness: 60HRC Height: about 25mm, 26mm, 35mm, 36mm Main material: Chrome vanadium steel Surface treatment: black electrophoresis Size: 1/2 "to 3/8" - (12.5mm square hole to the square head of 9.5mm) Length: 36mm 3/8 "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: 35mm 1/4 "to 3/8" - (6.3mm square hole to 9.5mm square head) Length: 25 mm Contneu: 4pcs Increasing and Reducing Adapters Note: this does not include other things, the color is based on the first picture and other pictures only show effect Due to the differences between different monitors, the picture may not reflect the actual color of the item. Due manual measurement. Please allow deviation. Thank you!