1 3/4″ inlet x 18 1/2″ long. Incl. 12 diffuser discs. Hi-temp coated black steel body with stainless core. Muffler bodies are 3 1/2″ diameter and flare out to 4″ diameter. No mounting bracket or slider channel is present. Note 1. Slip-on muffler assembly has no mounting bracket or slider channel present. Note 2. Includes a band style clamp for slip-on to header install.