This solvent still head is with two 0-4mm high vacuum valves for great solvent/chemical resistance. Syringe port has a 4mm PTFE stopcock and a 14/20 outer joint. Delivery port has 14/20 inner joint. Capacity of 500ml. Laboy glass flasks are heavy wall designed,made by hand-blowing to ensure uniform wall thickness, made of high-quality borosilicate glasss and annealed at 800 degree Celsius ,can be heated directly in an open flame and can withstand typical laboratory thermal variations in chemistry processes like heating and cooling.