29 mm threaded motor retainer. The HAMR (Highly Adaptive Motor Retainers) system has been designed specifically for use with any rocket kit using 29 mm PML motor tubes. These lightweight, tool-free, threaded retainers are precision CNC turned from 6061 aluminum and anodized. They fit virtually all popular motor brands and types.
The HAMR system can be adapted to existing rockets if the motor tube extends at least 9,5 mm (3/8”) beyond the aft centering ring. The HAMR can also be used with boattail and tailcone rockets. It is not possible to fit the HAMR on rockets already built unless you want to make a substantial surgery on the aft centering ring and fin tabs. A high-temp epoxy like JB Weld is necessary to apply the HAMR

Outer diameter of the threaded retainer ring: 38,6 mm (1.52”)