ALL COUPLERS COME IN 3" LENGTH AND ARE MADE OF HIGH TEMP 4-PLY SILICONE. 

4"  -   550,650,750 AFTERMARKET SYSTEMS, B PIPE CHAMBER TO MANIFOLD

4.5" 

4.75"  -  X2 & 650 & 750 Aftermarket exhaust systems, Westcoast, Jetsport, Butch's

ABOVE IS FOR REFERENCE ONLY AND ALWAYS MEASURE THE COUPLER OR EXHAUST YOU HAVE BEFORE ORDERING. 

ALL SIZES ARE INSIDE DIAMETER