These are the short belts that connect the X and Y motors to the axes. Official Ultimaker Spare Parts for the following printers: Ultimaker 2+ Ultimaker 2 Extended+ Ultimaker 3 Ultimaker 3 Extended Ultimaker 2 Go Ultimaker 2 Ultimaker 2 Extended Ultimaker S5...
Official Ultimaker Spare Parts for the Ultimaker 3, Ultimaker 3 Extended, and Ultimaker 2+ Connect. This is a complete set of 4 sliding blocks and long S2M belts.
Not compatible with other models or series of Ultimaker printers.
Installation instructions available here.