Malossi O2 Lambda Emulator for Yamaha S-Max 155COMPATIBILITY: S-Max 155Xenter 150iMalossi TC Unit 02 Controller Lambda Emulator for fuel injected Scooters. Corrects the Air/Fuel Mixture for optimum performance. Very simple Plug and Play installation. Your Scooter will run smoother and accelerate better from a stop. This is a must have item for any fuel injected Scooter.**NOTE: Electrical items are non-returnable so please check photos and specifications before ordering. Please see our Warranty and Returns Policy