The Kalme Day Defence SPF25 is a physical mineral sun block as opposed to a chemical SPF filter. SPF25 is the highest level you can get for a physical mineral block. 

Bare in mind that  a chemical filter SPF, even if it has a higher factor, does not have the same protection for skin and a physical mineral sun block. An SPF25 physical mineral block such as in the Day Defence SPF25 is the equivalent of approximately SPF50 in a chemical filter SPF.

Also bare in mind that chemical filter SPF's, especially higher ones, can often cause skin reactions in very sensitive skin such as skin prone to rosacea which is why we don't use them in Kalme products.