oil and lubes for bearings
Bearings for skates, scooters and skateboards need to be greased. Otherwise they are noisy, slower and likely to be damaged by humidity. As a grease can be used oils, vaseline or special gels for bearings. Generally oil provides better ride than tough vaselines, but they need to be refilled more often. Teflon, ceramic nano particles and other substances are added to greases in order to lower the friction.