Local bike shop bike shops have begun themselves to sell products online. A recent development is the introduction of brand specific stores from bicycle manufacturers such as Trek Bicycle Corporation. Other manufacturers, such as Specialized are strengthening their channels with "concept stores". According to the National Bicycle Dealers Association, in 2007 there were approximately 4,400 "specialty bicycle retailers" in the USA; down from 4,800 in 2005. Although they sold only 17% of the bikes, up from 16% in 2005, they collected 49% of the dollars, up from 47% in 2005. In 2004, the average specialty bicycle retailer had gross sales of $550,000 per
Bicycle chain 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. Notable bicycle chain manufacturers include: Bicycle chain 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.