Monoprice Select Mini X-Axis Belt Tensioner cap

This is a replacement end cap for the x-axis rods on the Monoprice Select Mini. This cap is longer than original, and provides a slot for the pulley assembly to slide in, so that you can tension the belt without using the spring tensioners, or other tensioners that ride on the belt.

The tension is adjusted by tightening the knob, which pulls the screw and moves the pulley assembly within the cap.

Also, the internal dimensions are tighter than the factory cap, so that the pulley cannot rot