The double manifold, also called vacuum gas distributaries usually used in Schlenk line. With 4mm double oblique, high vacuum solid glass stopcocks. The solid glass stopcocks have constant pressure retention devices. Distance between stopcocks is 100mm center to center. Laboy glass flasks are heavy wall designed, made by hand-blowing to ensure uniform wall thickness, made of high-quality borosilicate glass 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.