Ultimaker 2 UM2 GT2 belt coupler

This is a GT2 belt coupler that allows the use of open belts on ultimaker 2 (UM2) printer.
It fits inside XY carriage.
To use it :
- Cut the belt with 1 or 2 cm of extra length, then put a coupler on each end of the belt (the belt must be, of course, already on the pulleys of the printer).
- Put both couplers side by side, tensionning the belt, then measure the length that has to be removed.
- Cut the extra length (the pitch is 2 mm on a gt2). you may have to cut 2 extra mm to get good tens