SIP

SIP valves let you drink through a straw without taking off your mask. This is especially helpful when wearing a mask that is fiddly to get sealed, like N95s. Even though I mask every day, I don't use a SIP every day. I use it when I will be on public transportation, or at a conference all day. I bought 2 just in case, but have only used one in a year, on a few different masks.