Precision machining, made of heat-treated steel, with corrosion-resistant black phosphate surface. The 360-degree omni-directional motion enables the U-joint socket to rotate completely, reaching a narrow space and approaching the fasteners that are difficult to reach. High contrast size marks are permanently laser, which can be easily read even in low light conditions. A ball with a spring at of the rod locks the socket in place to safety and prevent it from falling. Packaging includes: 1 x 1/2 inch universal joint socket adapter 1 x 3/8 inch universal joint socket adapter 1 x 1 /4 inch universal joint sleeve adapter Colour:black Material:steel Package Contents: 3 x Wrench socket attachment Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.