A more successful series of calculators using a reflective DSM-LCD was launched in 1972 by Sharp Inc with the Sharp "EL-805", which was a slim pocket calculator. This, and another few similar models, used Sharp's "Calculator On Substrate" (COS) technology. An extension of one glass plate needed for the liquid crystal display was used as a substrate to mount the needed chips based on a new hybrid technology. The COS technology may have been too costly since it was only used in a few models before Sharp reverted to conventional circuit boards.