These steel exhaust spigots fit into your 1972 and up 750 c.c. OIF (oil in frame) Triumph motorcycle head and allow you to run earlier 650 c.c. exhaust pipes. The spigot end that fits into your head is 1.39″ and is a tap-in fit. Chill these adapters in the freezer, heat up the head lightly with a propane torch and tap these in place. The heat expands the aluminum, the cold contracts the steel adapters, and this allows easy assembly that tightens up nicely in place as the temperatures even out. These spigot adapters stick out 1.65″, allowing you to run the 650 Triumph exhausts that have a 1.75″ flare, and the stock style finned exhaust clamps. Sold in pairs. Made in Ohio, USA