FerMonster™ PET Fermenter With a wider 4” mouth, there is easier access for cleaning. It is made of heavy P.E.T. plastic. Our Carboys do not use any plasticizer and are made with 100% Virgin material. Made with Food grade materials and BPA free. Comes with an O-ring and air-tight ONE PIECE lid with a hole that will take our #10 bung (available under accessories). The lid hole is 4.3 cms (1.7”) in diameter. There are no ribs, only smooth sides, so no yeast or sediment will adhere to walls during fermentation. Completely taste and odour-free. It is also stain resistant. Impermeable to oxygen. 100% made in Canada. Comes with easy-to-read markings on the side. Also they are big enough so you can use them as your Primary Fermenter. .