Why is Comvita UMF 10+ so special? Comvita UMF 10+ Manuka Honey is guaranteed to be at least UMF 10. The UMF grading system appraises natural markers found in Manuka honey. The UMF grading system has two components which are expressed on any UMF licenced honey product: 1.The label claim that it is Manuka 2.The number - this represents three natural chemical markers that indicate the content of this honey to ensure purity and quality. These key natural chemical markers are DHA, MGO, and Leptosperin.