Autoclavable. Supplied with linerless GL 45 screw thread caps. Replaceable clear (natural) drip-free polypropylene pour ring is included on each bottle. The pack consists of two 100 mL, three 250 mL, three 500 mL, and two 1000 mL bottles. Manufactured from 33 expansion, low extractable borosilicate glass conforming to USP Type I and ASTM E438