These minimum diameter retainers offer everything you need for your next extreme MD project. Some highlights of these retainers are:
 
Very low profile that save space inside you rocket.
 
Single bolt construction offers superior retention as the bolt holding the motor is the same bolt connected to your recovery system. This also means you cannot accidentally take out the threaded rod when removing the motor.
 
Removable means it is more flexible. Retaining with screws allows the retainer to be removed to service the shock cord, or moved to another rocket when the current one is retired. If you rather, it can also be epoxied into place. 
 
Comes with a 1/8 quick release.