This tool should be used as a guide only. Penguard Express ZP may not be an exact match for Hempadur ZP 47940 by but we have given the closest match we can. Penguard Express ZP should do the same job and have similar properties but you should always read the technical data sheets for both Penguard Express ZP and Hempadur ZP 47940 to be sure. Please see any notes to see any major differences and call us on 01285 862132 if you have any specific questions.