The Silicon is an important part of the vacuum pumps to do quick maintenance on the O-rings. After you install your rack on your car, if you start to see the white safety indicator in less than 3 hours, do not use the rack, do a quick maintenance, and test it before you use it again! To put a small amount of Silicon on the O-rings, it will lubricate inside the vacuum pump and seal again perfectly. The perfect time to do a quick maintenance, before your session starts, or before you are planning a long trip and vacation. We recommend keeping the Silicon inside your car, when you do long trips or heading out for a long vacation.