Used for GY6 150cc 157QMJ based engine. Extra weld-on mounting flange is also included.If you don’t know how to do modification on head pipe,cut old flange off, welded on new flange to your stock head pipe will also be fine. Modifications in mounting of the Head Pipe may be necessary.You may also have to Grind a Half Moon Shape in one of the Mounting Brackets to Clear the Engine Dip Stick On some models once the Head Pipe is mounted it may need to be heated and slightly bent out for clearance and alignmen A great up-grade 7 inch length exhaust system when installing a big bore kit or a great replacement exhaust for a broken stock exhaust system. Package includes all the parts showing in images. Product description Potentially add more performance, speed and power to your bike with this high performance exhaust pipe. Also provides a stylish look and a deeper exhaust tone Fits on many models of GY6 Scooters and Mopeds Four