The Nortech N886 Exhaust Silencer Foam Insert For "M" Venturi Vacuum Heads Is ASound-Absorbing Foam Insert That Functions As Muffler To Reduce Noise Levels. Fits Inside Exhaust Silencer Housing. The Nortech N686 Exhaust Silencer Foam Insert For "M" Venturi Vacuum Heads Features: * Diameter: 4.5" * Height: 8.5" * Weight: 0.1 Lbs. * Made In USA * SKU690773018199>