Power transmission chain and chain sprockets are used to transmit mechanical power from one rotating shaft to another. A chain drive consists of at least two sprockets and a roller chain that interlocks with the sprocket teeth. Chain sprockets with more teeth carry heavier loads but they produce more friction, which reduces operating speeds. Roller chain is lubricated to reduce friction and wear. Accessories like chain wear gauges measure the amount of space between chain links to determine if a chain is too worn. Worn chains can jump out of sprockets and must be replaced.