Lead screw diameter 8mm, length 500mm Copper nut, with 4 holes for fixing to the machine : Screw pitch: 2mm; Lead: 8mm If you want higher precision, it is recommended to use the anti-copper nut. Size: T8x8 The lead is 8mm, which means the nut will move 8mm if it rotates one circle. The advantages of the screw are: Large load capacity Compact Large mechanical advantage Accurate and precise linear movement Smooth, quiet and low maintenance, very suitable for the z of the 3D printer. Minimum number of parts So this lead screw is very suitable for the Z of the 3D printer, such as and Prusa i3. The screw type of this lead screw is the thread. Threads are generally stronger than square threads due to their trapezoidal profile, which provides better capacities load. Color: Silver + Gold Material: Stainless Steel Package Contents: 4 x 500mm Lead Screw 4 x Copper Nut Only the above package content, other products are not included. Note: Light reflection and different displays may cause the