Vacuum Exhaust Mufflers Porous Plastic Mufflers Model No. M-18/30 ANVER Part Number Exact Replacement For P-Series Muffler No. AThread NPT BDiameter in. (mm) CLength in. (mm) Filter Size Microns Weight oz. (g) M-18/30 N125FF 1/8″ 0.50 (12.7) 1.15 (29) 30 0.03 (0.85)