This insert works as advertised. It reduces the sound output of your exhaust but, as far as I can tell, does not affect the power output of the bike. A good product if you are close to the sound limit at your local track.
Do your part in keeping noise levels to a minimum by adding one of Pro Moto Billet's new style turn-down silent inserts to your Endos spark arrestor end cap.
This new generation version of the Pro Moto Billet silent insert is less restrictive and performs better than its predecessor.
Insert fits all new style color anodized "cone" type Pro Moto Billet spark arrestor end caps (Endos) and reduces the exhaust note by 3 - 5 decibels* for a more acceptable sound intensity level.
Requires a Pro Moto Billet Endos spark arrestor to install.
NOTE: These Will NOT fit Pro Moto Billet's older style polished "snorkel" style end caps. (If your end cap is bright polished aluminum, then you have Pro Moto Billet's older style end cap.)
*Sound intensity level will vary depending on model, tuning, and exhaust system condition.