Belt tensioner for Prusa I3 X axis

This belt tensioner fits into the open side of the right part of the X gantry of the Prusa I3 reworked set.
I am still overworking this design, but it is already functional.
Additional parts:
1 x M4 nut
1 x M4 screw 30 - 40 mm.
The belt will slide over the rounded part of the belt tensioner. I used PLA and the belt really slides very well without any noticeable force.
However I will redesign everything over time and also try IGUS special filament with ultralow friction in a second ve