For UMO with standard x/y shafts - x2 m3 20/25mm screws for each slideblock (20mm for bottom slideblock it's mandatory or will Hit the Z long rods) - x2 m3 nuts for each slideblockr - x2 m3 16-20mm screw for each umo shaft adapter - x2 m3 nuts for each umo shaft adapter When assembling it it's very important to keep a good sandwich between the parts (when using the umo shafts adaptor) so when the screws go in they don't push the parts. VERY IMPORTANT, for the gt2/mxl belt grip to have the holes pre-marked with a screw or with a m3cap, so the assembly will be much easier. ALSO: I have not tested the MXL belt grip, it should work, but I don't use anymore mxl on any of my machines. For UMO with UM2 shafts - x2 m3 14-16 for each slideblock - x4 m3x10mm for each belt grip to 'grip' the um2 shafts. Screw them after assembling the gt2/mxl grip.