These mufflers fit 2" header collectors, and are a great addition to any header set. With Micro Sprints in mind, they feature a re-packable glasspack core, stainless steel construction, and a carbon fiber or stainless steel housing. Mufflers include the housing clamp to mount to a bracket, a T-bolt muffler clamp to attach it to your header collector if desired, and a pair of springs/tabs if you wish to use springs instead of the T-bolt clamp. Spring tabs are already installed on the mufflers. The use of springs would require welding of the tabs to your header collector if not already present. To use the T-bolt clamp, you'll need to cut off the existing spring tabs, and cut two slots on the inlet end to allow for the muffler to clamp down on your exhaust pipe. Mufflers are sold individually.