A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. In order to reduce weight, chains have been manufactured with hollow pins and with cut-outs in the links.Chains have also been made of stainless steel for corrosion resistance and titanium for weight reduction, but they are expensive.A recent trend is chains of various colors, and at least one manufacturer offers a chain model specifically for electric bicycles.