PC. With PP stopcock and PP screw cap (83 mm). Gasket made of TPE. These tough, glass-clear, autoclavable carboys are ideal for dispensing sterile water, aqueous reagents and media. Use in cold rooms, even at freezing temperatures. Stopcock boss molded in one piece with bottle, for strength and leak resistance. Graduated to deliver in 1 gal and 5 l increments. Leakproof. PC. With PP stopcock and PP screw cap (83 mm). Gasket made of TPE. These tough, glass-clear, autoclavable carboys are ideal for dispensing sterile water, aqueous reagents and media. Use in cold rooms, even at freezing temperatures. Stopcock boss molded in one piece with bottle, for strength and leak resistance. Graduated to deliver in 1 gal and 5 l increments. Leakproof.