ULTRA Silent Insert [PMB-01-0012] ULTRA Silent Insert NEW! Our new Ultra Silent insert further reduces sound levels with a reduction range of 4-6 decibels*. Same great fit, finish, and easy installation as our standard silent insert. Fits all new style color anodized "cone" type Pro Moto Billet spark arrestor end caps. Requires a Pro Moto Billet Endos spark arrestor to install. NOTE: These Will NOT fit our older style polished "snorkel" style end caps. If your end cap is bright polished aluminum, then you have our older style end cap. *Sound intensity level will vary depending on model, tuning, and exhaust system condition.