These 12" Universal Stainless Steel Muffler are just what you need for your project. They have an awesome look and a great sound to match. Constructed completely out of stainless steel and finished off with a brush look. They have a 12 1/2" ID for the inlet. These will fit most 4in1 CB750 exhaust headers.   The mufflers are manufactured by Cone Engineering right here in the good old USA. All their 12" Shorty mufflers are designed with a 1:1 ration for the inlet & Outlet diameters which procduces great power in the low end to mid range.

Cone Engineer 12" Stainless Muffler Specs: