Size: ID 4 inch exhaust adapter reducers(ID 4" to ID 4").It shares same inner 4 inches size on both sides,flare from the middle line.The exhaust adapter can be welded or clamp together.
One piece construction without welding, manufactured with precision bends and OE-style routings,heavy duty 16-Gauge stainless exhaust connector coupler for longer life
The surface of this 4 inch exhaust adapter is polished and shiny. You can weld or use clamp to hold this adapter with your existing exhaust system.