4" Clamp On Dual Stage Muffler6" X 10" long designed to push on 4" exhaust outlet. True performance stainless steel through transom mufflers that silences motors up to 500 horsepower without sacrificing power. It works so well that we have a patent on the design. Our internal silencing chambers, plus integral flapper help to eliminate engine backwash, while reducing the decibel levels through out the entire RPM range. Use the 4" clamp on version with your existing tips. 02-2464 replacement flaps are also available.(SOLD IN PAIRS)