Silicone O-rings are round, highly temperature resistant devices that seal connecting pieces in machinery where flexibility and longevity are important. These O-rings are resistant to UV damage, corrosion, oils, chemicals and solvents. They are used for electrical insulation and are dielectrically stable. Silicone O-rings aren't toxic, and therefore are FDA approved to be used in food handling equipment and appliances.
Silicone is an inert material, meaning it doesn't react with most chemicals. The medical industry therefore uses it for applications like complex medical implant systems that have moving parts requiring a sealant such as an o-ring. The aerospace, automotive, food processing and jewelry industries use silicone O-rings in their machinery and tubing or piping systems as well. Silicone o-rings sometimes require the use of a lubricant, if the two pieces it is wedged between are moving pieces. The lubricant protects the silicone from quick deterioration. This is a common thing among all o-rings, whether they are metal or rubber, flat or round. Silicone o-rings are naturally an opaque and partially transparent color, which is why they are sometimes called clear o-rings. However, clear o-rings are also produced from other materials such as Teflon, and silicone o-rings can be altered to match any color available.
Silicone O-Rings - Arizona Sealing Devices, Inc.