The Reed stuffer fits the BGM type Yamaha 350 YPVS and Banchee reed blocks.
NOTE these are slighty different to genuine Yamaha reed assemblies.
Its used with the MB TS1 inlet manifold so the manifold aligns into the stuffer and filling 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.