For tightening the X belt on a cupcake from MakerBot insdustries. Other tensioners on this site did not fit mine, also everyone else calls X Y and Y X? not sure who is wrong.make it tight enough and suddenly the machine gets quite quiet. good for the steppers? probably not.Real simple, remove your X belt pully, press the slider onto the upper nut, start the two bolts into the two nuts that hold the two halves together, then fight like the Dickens to get the whole doo-dad back in place. Tighten to your hearts contetn, mine bottoms out right as it gets tight, due to luck more than anything.Notes or places you could improve it:Parts needed: 1 x X belt slider (print me!) 1 x X belt Nut Side (print me! [also come up with a better name]) 2 x m3x16 bolts, shorter can work 2 x m3 nuts 2 or more small fingers and tools