Toothed belt

A timing belt, toothed belt, cogged belt or cog belt, or synchronous belt is a non-slipping mechanical drive belt. It is made as a flexible belt with teeth moulded onto its inner surface. It runs over matching toothed pulleys or sprockets.

When correctly tensioned, they have no slippage and are often used to transfer motion for indexing or timing purposes (hence their name). They are often used in lieu of chains or gears, so there is less noise and a lubrication bath is not necessary.