This part is an accessory for the MakerGear M2. It is designed to clip around the heated bed wire connector, and it serves the dual purpose of keeping the heater connector from separating, and preventing the wire from kinking behind the connector. Newer versions of the M2 (mine is from January 2013) use strong and flexible automotive cable on this connector, but the earlier versions can break the wire after enough flexing.

m2_splint_v5.stl is an updated version that better follows the natural curve of the cable. The fingers on the flexible part are longer and slightly curved to better hold the cable, and there is an additional notch on the side to accomodate the thermocouple wire.