Coffee Caps - Mason Jar Coffee Storage System - Let Your Beans Breathe One-Piece, Self-Sealing, Silicone Coffee Bean Storage Solution Let Your Beans Breathe without Exposure to Unwanted Oxygen Patented one-way valve allows trapped carbon dioxide gas to escape and prevents oxygen and moisture from getting in, Preventing Beans from Spoiling 2 Coffee Caps included (dark roast and blonde color), Dishwasher Safe, BPA- and Phthalate-Free Fits any "Wide-Mouth" Mason Jar (Ball, Kerr, Bernardin, etc.) - Screws on with any "Wide-Mouth" Mason Jar Band (not included)