Lead screw diameter 8mm, length 500mm Copper nut, with 4 holes for fixing to the machine Thread: thread Screw pitch: 2mm; Lead: 8mm If you higher accuracy, it is recommended to use the anti backlash copper nut Size:T8x8 The lead of the thread is 8mm, which means that the nut will move 8mm if the nut turns one circle. The advantages of the leadscrew are: load carrying capability mechanical advantage Precise and accurate linear motion , quiet, and low maintenance, very suitable for 3D printer z axis. number of parts So this lead screw is very suitable for 3D printer Z axis, such as and Prusa i3. The screw type of this lead screw is thread. Threads are generally stronger than square threads due to their trapezoidal thread , which provides greater load-bearing capabilities. colour:Silver + gold Material:stainless steel Package Contents: 1 * 500mm lead screw 1 * copper nut Only the above package content, other products are not included. Note: Light 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.