29mm Motor Retainer. For airframes 2.2" (54 mm) and up.

Both the 24mm and 29mm motor retainers have the same mounting hole arrangement which allows both retainers to be used interchangeably on the same rocket - i.e. use the 29mm retainer when using 29mm motors, use a 24/29 motor adapter and 24mm retainer when using 24mm motors.

Threaded inserts allow retainer to be added after model is built.