Watershed’s recommended lubricant for our ZipDry closure in a handy 3.4oz. bottle with applicator. Using 303 regularly is the very best way to keep your bag easy to open and close, and prevent any wear and tear on your thumb tabs. We highly recommend using on both sides of the seal before storing your bag and more frequently if you live in dry locales. 303 is the leader in UV screening technology and 303 Aerospace Protectant really is like “SPF 40 Sunscreen … For Your Stuff.” Regular use of 303 Aerospace Protectant can reduce UV caused slow-fade by up to 100%. No other protectant beautifies as intensely, protects as powerfully, or lasts as long.