4"/98mm Cluster Centering Ring for two 38mm motor tubes. 1/4" plywood.

Fits into any 4" airframe. Works best with Rocketarium 38mm(T), PML phenolic 38mm Tube and LOC fiberglass 38mm motor tube. (41.8mm motor tube OD)

- 41.85, - 98.9mm,  6mm,  21g