Flowtech Purple Hornies GlasspackThe classic Purple Hornie tubular design glasspack mufflers give sound and performance gains that are more than impressive they're wild! The 16 gauge, 3. 5" 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. 250" slip fit or choose from three different styles of 3"