LOCK & LOCK INTERLOCK DOOR POCKET PRESS BOTTLE 1.3LTR. Materials: rubber (silicone rubber), low-density polyethylene, polypropylene, and polyethylene terephthalate (PET). "Breathable" valve and pressing plate for excellent fermentation and ripping, ideal for arranging and storing fermented foods in the refrigerator Fermented food components are easily poured off.