Turning off a rough vacuum pump connected to a chamber creates a vacuum effect in the opposite direction. This effect will often cause the oil contained inside of the pump to flow in the direction of the chamber (backstreaming) and risk contaminating the samples and the environment inside of it. The Oil Trapping Sphere provides an economical option for preventing the backflow of oil. It does this by creating an obstructive path for the oil using the curve of its wall. It is made of stainless steel and connects to the vacuum pump inlet and bellow by using KF25 flanges. (click here to order Stainless Steel Vacuum Fittings, Pipes & Valves ) Specification Bottom Flange Top Flange Diameter Height KF25 Type KF25 Type 100mm 134.5mm