Tough-PAC PDA is a hard shell case for iPod touch 5th, 6th or 7th generation. Biomaster silver ion technology is incorporated during manufacture. This inhibits growth of contaminating bacteria and fungi by more than 99.6% for the life of the product. It's not a coating, it's permanent. The only medical grade case system for iPod Touch Tested to ISO22196 international antimicrobial standard.