Electronics technicians help design, develop, test, manufacture, install, and repair electrical and electronic equipment such as communication equipment, medical monitoring devices, navigational equipment, and computers. They may be employed in product evaluation and testing, using measuring and diagnostic devices to adjust, test, and repair equipment. Electronics technicians may also work as sales workers or field representatives for manufacturers, wholesalers, or retailers giving advice on the installation, operation, and maintenance of complex equipment and may write specifications and technical manuals. Electronics technicians represent over 33% of all engineering technicians in the U.S. In 2009, there were over 160,000 electronics technicians employed in the U.S. Electronics technicians are accredited by organizations such as the Electronics Technicians Association (ETA), or International Society of Certified Electronics Technicians (ISCET).