A belt tensioner for your Migbot I3. You will have to drill a hole for the adjuster screw. The screw should be an M3x30 but if you feel adventurous, you can countersink the hole and use an M3x20 screw and nut. You will also have to trim about 30mm from the timing belt to make this work.This was printed with PLA at .3mm but ABS can also be used. The bracket was made using supports. You can use the base as a template to drill the hole for the adjuster screw. Just temporarily mount it on the opposite side of the frame and make the hole.