Anet A8 S Y Belt Tensioner

This Y tension is for the Aluminum clad Anet A8 Z or S... I'm not sure of their designation.
Some parts are the same on these machines, but others are different, like the Y pulley.
I printed in PLA with 20% infill. It uses M3 hardware and is made to use a 16 tooth pulley.

You'll also want to print at least 2 hold downs if not 4 to secure the unit to a 2x2 board or work work desk.