Aeropack 54 mm Flange Retainer [RA54]. Madcow Rocketry / Aeropack : Rocketarium Model Rocket Kits, parts and launch supplies

54 mm Rocket Motor Retainer Assembly.

Light-Weight Assembly For 54mm. Fastens too lower centering ring with flange and included hardware
Large Quick-Turn Threads For Fast, Tool-Free Motor Change
Installation: Mounts to lower centering ring with 6 threaded inserts and 6 stainless steel socket head cap screws.
Just Slide Motor In And Thread On Cap, That's It!
Can Be Installed On Existing Rockets. Minimum airframe I.D. = 3 inch.