Grand Rock Mufflers are manufactured using the same standards we use on all our great products. These standards are what sets us apart from the competition. We do not compromise the thickness of steel used on muffler inlets and outlets. We use the same steel thickness throughout the muffler construction. Besides the steel thickness Grand Rock is using domed tops (also known as bullet top) on most of our applications. This prevents water from settling on the top of the muffler, causing corrosion, shortening your mufflers life span. It’s these little things we focus on that make a BIG difference between us and our competitors.