This stopcock grease is ideal for lubricating and sealing glass stopcocks used in high vacuum apparatus. At room temperature, the vapour pressure is low enough for the material to be suitable to be used in thermionic experiments. Vapour pressure, 10-3 mm at 200°C; 10-8 to 10-9 at room temperature. The safest maximum temperature in use is 30°C. Can be applied at room temperature, but the stopcocks should be lukewarm before assembling. Comes in 25 gram tube.