54 mm to 38 mm centering ring holds 38mm motor tube inside 54mm motor tube. 1/4" plywood.

Fits into any 54mm airframe. Works best with Rocketarium 38mm (S), LOC and Madcow 38mm Cardboard Tube, Blue Tube (41.6mm motor tube OD)

- 41.6mm, - 54.15mm,  6mm