Material: Chrome vanadium steel CR-VType:Hex Drill Nut Driver Power Extension BarSize:1/4 x 1/4 x 50mm length ------ 1/4" shank can be converted to 6.35mm square head3/8 x 1/4 x 50mm length ------ 1/4" shank can be converted to 9.53mm square head1/2 x 1/4 x 50mm length ------ 1/4" shank can be converted to 12.7mm square head1/4 x 1/4 x 65mm length ------ 1/4" shank can be converted to 6.35mm square head3/8 x 1/4 x 65mm length ------ 1/4" shank can be converted to 9.53mm square head1/2 x 1/4 x 73mm length ------ 1/4" shank can be converted to 12.7mm square head1/4 x 1/4 x 25mm length ------ 1/4" shank can be converted to 6.35mm square head1/4 x 1/4 x 30mm length ------ 1/4" shank can be converted to 6.35mm square headUses: Suitable for a screwdriver handle or electric screwdriver tool (hexagonal hole or three-jaw chuck)drive sleeve to use. After install the original hexagonal size can be converted to square head size,so use to install the sleeve.Package includes:3Pcs Short :1/4 x 1/4 x 50mm + 3/8 x 1/4 x 50mm + 1/2 x 1/4 x 50mm3Pcs Long:1/4 x 1/4 x 65mm + 3/8 x 1/4 x 65mm + 1/2 x 1/4 x 73mm8Pcs Set:1/4 x 1/4 x 50mm + 3/8 x 1/4 x 50mm + 1/2 x 1/4 x 50mm1/4 x 1/4 x 65mm + 3/8 x 1/4 x 65mm + 1/2 x 1/4 x 73mm1/4 x 1/4 x 25mm + 1/4 x 1/4 x 30mm