Semroc Centering Rings Fiber BT-20 to ST-11(2pk) SEM-CR-20-11
Featherweight laser-cut fiber rings which center a BT-20 tube inside a ST-11 series tube. Especially useful for making a standard engine mount for ST-11 rocket bodies. Thickness is .050".
I.D = 0.736
O.D = 1.13