Is mask washable? Yes What kind of straw to use? Recommend metal 8.5 straw or any regular size straw Does mask fog up glasses? No How many layers of protection? 2 layers Are straps adjustable? Yes Is mask easy to breathe in? Yes has great comfortability for breathing Does valve open completely? No it’s an airtight holes that grips around the straw and automatically seals after each sip allowing you to drink safely