This tool should be used as a guide only. Hardtop AX may not be an exact match for Korethan Topcoat UT6581 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 Korethan Topcoat UT6581 to be sure. Please see any notes to see any major differences and call us on 01285 862132 if you have any specific questions.