A Belt Unit or Transfer Belt serves the function of collecting toner powder particles from each photoreceptive drum unit. Each drum unit will contain an electrostatic image pertaining only to the color of the toner being applied. Most color laser printers will contain four different drums for each color (cyan, magenta, yellow and black). Other laser printers will vary depending on the amount of individual toner cartridges inside the machine. As the belt passes over each drum, the original image will develop on the belt, layer by layer, color by color. Once the belt has passed and collected toner from each drum unit, the belt will carry the toner to one last transfer roller. The last transfer roller will emit a high-voltage, static pulse attracting the toner from the transfer belt toward the roller, to be intercepted by a passing piece of paper. Any leftover toner particles on the belt will be cleaned (or scrapped) off by a small rubber blade before starting the process all over again. Inkgrabber.com offers the Original Equipment Manufacturer (OEM) or Genuine Transfer Belt Units which are created by the printer manufacturer. All products, including the Brother OEMBU100CL, are ISO 9001 certified, meeting the highest standards and offered at only $112.99. Every Genuine Brother Belt Unit Assembly has up to a 2-3 Year shelf-life and is backed with the Inkgrabber 90 Day Money Back Guarantee. In addition Inkgrabber.com also provides a 1 year exchange policy for damaged or faulty hardware.