This tool should be used as a guide only. Mare Nostrum SP may not be an exact match for Protector Antifouling by but we have given the closest match we can. Mare Nostrum SP should do the same job and have similar properties but you should always read the technical data sheets for both Mare Nostrum SP and Protector Antifouling to be sure. Please see any notes to see any major differences and call us on 01285 862132 if you have any specific questions.