Super 44 - 2.25 Offset In / 2.25 Center Out - Aggressive Sound; Flowmaster s Super 44 muffler uses the same Delta Flow technology found in our larger Super 40 mufflers. The Super 44 delivers a powerful rich tone and is the most aggressive deepest sounding highest performing four inch case street muffler we ve ever built! Constructed of 16 gauge aluminized steel and fully MIG welded for maximum durability.;