Different standard sizes for various hole spacings and M4 (EU standard) and #8-32 UNC (US standard) screws are available. The smaller handles slightly differ in shape, so there is enough space to grab the handles. Slicer file also included! Set max. 0.16mm layer height. Use standard screws M4 (EU) or #8-32 UNC (US) to mount the handles. Don“t tighten the screwdriver too much!