The 304 Series mufflers are made from high-quality 304 stainless steel that can be polished to a show- winning finish. They utilize a new high-flow core design and our unique, high-temperature ceramic packing and stainless steel wool for outstanding performance and durability. In flow bench tests, the new #5560 flowed 495 cfm, an improvement of more than 100 cfm over a leading competitor. Available in 2-1/4", 2-1/2" and 3" sizes in center in/center out, center in/offset out, and offset in/center out configurations.