For Tarot and similar carbon fiber arms with 25mm OD and 23mm ID. This cap protects motor wires from pinch damage where they enter motor arm tubes on 850-class multi-rotors. The part allows a folded multirotor to be stored on-end, and is also effective protection in the event of a crash.
Disconnect motor wires from ESC. Loosen motor mount clamps, slip in end cap and re-tighten. Push wires or bullet connectors through end cap and through motor arm tube. Reconnect motor wires to ESC.
Due to slight variation in tube diameters, a little sanding or a little adhesive may be required. An impermanent adhesive, like silicone is recommended.
This product is also available for 16mm motor arms.
The photos show the 16mm version, printed on a FFM machine.