This is a cable guard (or guide) of variable length, it helps to reduce cable wear in linear movement applications.All the parts click together and you can simply print as many middle sections as you need. There are three slots inside for the cables, 2 x 4.5mm and 1 x 8.5mm in the middle. The cable chain section is 30mm wide in the filesThe example on the photos is printed in PLA on the UM2 and has 14 middle sections which makes it about 335mm long.