The exhaust is made of aluminum with stainless steel connector Hexagon shape looks very attractive and cool Stainless Steel Welding Adaptor Allow To Fit Pipe 38mm – 51mm It Is Universal Muffler Can Be Used For Dirt Bike, Street Bike, Scooter, ATV, Quad And Any Other Bike With Pipe Diameter 38-51mm Include all necessary mounting accessories Specification: Color: Titanium As Pictures Material: Aluminum Length: 390mm Connection Diameter: 51mm we have a welding bracket to fit pipe with outlet 38-51MM. It Is Universal Muffler Can Be Used For Dirt Bike, Street Bike, Scooter, ATV, Quad And Any Other Bike With Pipe Diameter 38-51 mm.