Silicone grease, sometimes called dielectric grease, is a waterproof grease made by combining a silicone oil with a thickener.
S 1465 (OTTO) Silicon high vacuum grease (lab) - used for lubricating and preserving rubber parts, such as O-rings. Additionally, silicone grease does not swell or soften the rubber, which can be a problem with hydrocarbon-based greases. It functions well as a corrosion inhibitor and lubricant for purposes that require a thicker lubricant.