Standard original exhaust for GY6 125/150cc engines. There are various exhaust systems for these engines. The main difference is in the mounting of the system. The system listed here is additionally fixed to the engine case on the rear swing arm. Please note the product images. Exhaust system without SLS, but can be used on vehicles with the SLS. In this instance, the air connection and hose are to be placed inside the fairing and blanked-off. This increases performance over having an active SLS.