This is the Du-Bro R/C Bolt-On Pressure Fitting. FEATURES: Brass pressure fitting. Brass nut. Fiber washer. Easily mounts anywhere on the muffler by drilling a hole and bolting it or taping a smaller hole. Tapping instructions provided. INCLUDES: (1) Bolt-On Pressure Fitting REQUIRES: #36 Drill #28 Drill kr4/29/04 ir/jxs