This tool should be used as a guide only. Hardtop AX may not be an exact match for Hi-Urethan No. 5800S Topcoat by but we have given the closest match we can. Hardtop AX should do the same job and have similar properties but you should always read the technical data sheets for both Hardtop AX and Hi-Urethan No. 5800S Topcoat to be sure. Please see any notes to see any major differences and call us on 01285 862132 if you have any specific questions.