Can work with gt2 timing pulley I printed at 0.2mm layer height with 30% infill with 2x line multiplier on cura.It is pretty solid and easy to print no need for support.It has 5mm boreIt has a hole for m3 bolts and screws.It is pretty cheap to print also as you can see from the picture.I printed with esun PLA+ and it is quite strong.