Genuine Tohatsu Thermostat Gasket to fit the following models (will also fit Mercury / Mariner models)
2–2.5 hp
Tohatsu MFS2, MFS2A, MFS2B
Tohatsu MFS2.5, MFS2.5A, MFS2.5B
3.5–4 hp
Tohatsu MFS3.5, MFS3.5A, MFS3.5B
Tohatsu MFS4, MFS4A2, MFS4B, MFS4C
5–6 hp
Tohatsu MFS5, MFS5A2, MFS5B, MFS5C
Tohatsu MF6, MFS6, MFS6A2, MFS6B, MFS6C
Compatible outboard models
Tohatsu four-stroke models:
MFS8A, MFS8A2, MFS8A3
MFS9.8A, MFS9.8A2, MFS9.8A3
MFS9.9B, MFS9.9B2, MFS9.9C
MFS15B, MFS15B2, MFS15C
MFS18B, MFS18B2
MFS20C
MFS25A, MFS25B and MFS25C (up to 2018)
MFS30A, MFS30B and MFS30C (up to 2018) 
If unsure please get in touch with your outboard model and serial