The 50 Series Heavy Duty Muffler is appropriately named, a tough customer just like the trucks it was designed for. With 4.00” internal components and large case size, these mufflers help to significantly increase mileage, torque, and horsepower while greatly improving towing power and acceleration. The 50 Series Heavy Duty is great for all gas and diesel applications, and late-model trucks used in the most extreme working conditions. Constructed of 16-gauge aluminized steel and fully MIG-welded for maximum durability.5" Thick x 10" Wide x 18" Long with inlet/outlet sizes from 3" up to 4". Click on image for sizes and full part number listing.