Complete solution for for the 4 cylinder K series, exhaust collector include muffler. Durable and stylish design, great addition to the retro motorcycle. Nice working welds, the product is made of stainless steel. The package doesn't contain exhaust springs. Without TÜV and certificates. Please be advised that collector is a universal part sold also with other mufflers so maybe some modification during installation will be needed "shortening" Package includes: 1xmuffler collector 4to1 Installation: To fit collector please release screw mounted on head of engine (4exhaust pipes) then slide collector on pipes?