This Reed stuffer fits the BGM type Yamaha 350 YPVS and Banchee reed blocks. NOTE these are slighty different to genuine Yamaha reed assemblies. Ideally used with our own MB TS1 inlet manifold so the manifold aligns into the stuffer which fills the gap on the entry to the reed petals. In theory this speeds up air flow and increases power and throttle response. In practice, it compliments the very reliable BGM Yamaha reed assemblies with the MB TS1 flange inlet manifold.