A well-proven and recommended high-vacuum grease for electron beam instruments. Grease L is a petroleum hydrocarbon grease, containing no additives. Very low vapour pressure (@20 deg. C of 8x10-¹¹ torr), high vacuum grade. Type L is widely used in electron microscopy where moderately high column temperatures and high vacuum requirements demand a vacuum grease with extraordinary characteristics. Type L is also used in the stationary phase of gas liquid chromatography, and may be used on all ground joints in a vacuum system (not for stopcocks). Its solubility is as follows: in ethanol at 20 deg. C-0.003%; 60 deg. C-0.005%; 100 deg. C-0.011%; 150 deg. C-0.011%. Grease L softens and melts at about 47 deg. C and it is not recommended for joints where temperatures exceed more than 30 deg. C in use. Grease T is recommended for these higher temperatures.