This tool should be used as a guide only. Tankguard HB may not be an exact match for Interline 904 by but we have given the closest match we can. Tankguard HB should do the same job and have similar properties but you should always read the technical data sheets for both Tankguard HB and Interline 904 to be sure. Please see any notes to see any major differences and call us on 01285 862132 if you have any specific questions.