Please don’t waste your money. You would be better off paying more $$$ for accuracy and reliability of other tests. Sweat collected in the patch and stuck to my arm the entire hour long run, no problem, but it never scans or voids out at the end anyway. The app has some major software glitches it needs to work through. I blew through $50 worth of patches before just giving up-it never successfully scanned the patches. Going with Levelen instead