What Our Gearhead(R) Experts Are Saying:"I keep a spare in my vest pocket after a valve wore out mid-run last season. It's a quick swap on the trail and keeps dirt out of the nozzle on dusty days."Small parts matter most when they're the ones you never think about, and the Soft Valve Cover keeps your flask running clean mile after muddy mile. Toss a spare in your vest pocket before a dusty trail run, swap it in seconds if a valve wears down, and never worry about grit finding its way into your water again.