54 mm to 38 mm centering ring holds 38mm motor tube inside 54mm motor tube. 6mm plywood.

Fits into any 54mm airframe. Works best with Rocketarium 38mm(T), PML phenolic 38mm Tube and LOC fiberglass 38mm motor tube. (41.8mm motor tube OD)

- 41.85, - 54.15mm,  6mm