This is a drain plug O-ring for the 290-DP, DP-E other DP drives listed below. This is one option for an MS25S Saildrive whereas the other option, part number 3855081 is a fabric gasket.
Volvo Penta green coolant gives vastly superior corrosion protection with special additives for aluminium protection. Suitable for both petrol and diesel engines. It also has good anti-freeze properties
These are the 4 Rubber plus that holds the top engine cover on.
Companion flange O-Ring for KAD series and other diesel engines