Mfg.,Part No.,COUPLERS,Units,ID,OD,Length,Material,Mass Units,CG,Mass,AutoSize Always Ready Rocketry,BT20-29C,29mm Blue Tube 2.0 Coupler,in.,1.017,1.141,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-38C,38mm Blue Tube 2.0 Coupler,in.,1.394,1.515,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-54C,54mm Blue Tube 2.0 Coupler,in.,2,2.124,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-63C,2.56 in Blue Tube 2.0 Coupler,in.,2.418,2.542,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-75C,3 in Blue Tube Coupler,in.,2.873,2.997,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-98C,4 in Blue Tube Coupler,in.,3.764,3.888,8,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-139C,5.5 in Blue Tube Coupler,in.,5.19,5.338,12,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-152C,6 in Blue Tube Coupler,in.,5.835,5.976,12,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-191C,7.5 in Blue Tube 2.0 Coupler,in.,7.35,7.483,12,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-139C,5.5 in Blue Tube Coupler - Long,in.,5.19,5.338,16,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-152CL,6 in Blue Tube Coupler - Long,in.,5.835,5.976,16,Vulcanized Fiber,oz.,0,0,1 Always Ready Rocketry,BT20-191CL,7.5 in Blue Tube 2.0 Coupler - Long,in.,7.35,7.483,16,Vulcanized Fiber,oz.,0,0,1