Crown Bees Mason Bee Accessories, Bee Guardian This sealable bag is made from industrial organza fabric providing a protective barrier between developing bees and hungry predators Fits two large (96-hole) mason bee wood trays, two large (104-hole) leafcutter trays or approximately 400 tubes Double-Drawstring firmly secures the bag entrance The ultra fine mesh fabric helps to safeguard developing bees while allowing moisture to escape