"Flowtech 50225FLT Purple Hornies Slip Fit Muffler Have You Got The Purple Hornies? The classic Purple Hornie tubular design glasspack mufflers give sound and performance gains that are more than impressive-they're wild! The 16-gauge, 3 1/2"" diameter steel shell encloses an interior spiral louver baffle design that increases exhaust velocity while decreasing backpressure, projecting the sound waves into a temperature fibermat material. Available in an 18"" case length with 2 1/4"" slip-fit or choose from three different styles of 3"" three-hole direct-header-mount designs."