37 Repair or maintenance of optical machines and apparatus; repair or maintenance of telecommunication apparatus and instruments, namely, wire communication machines and apparatus, transmission machines and apparatus for telecommunication, radio communication machines and apparatus, radio machines and apparatus, remote control telemetering machines and instruments, video frequency devices and apparatus, parts and accessories for telecommunication machines and apparatus; repair or maintenance of electric motors; repair or maintenance of power distribution or control machines and apparatus; repair or maintenance of power generators; repair or maintenance of laboratory apparatus and instruments, namely, laboratory experimental machines and apparatus for use in measuring, analyzing, or simulating fuel economy and emissions of internal combustion engines; repair or maintenance of measuring, testing, or analyzing apparatus and instruments, namely, on-board emissions measurement apparatus and instruments, portable emissions measurement apparatus and instruments, measurement apparatus and instruments for exhaust gas on vehicle, emissions measurement apparatus and instruments, vehicle testing apparatus and instruments for use during a vehicle emissions test, drive-line testing apparatus and instruments for use during a drive-line test, engine testing apparatus and instruments for use during an internal combustion engine emissions test, parts and fittings for all the aforesaid goods; repair or maintenance of chemical processing machines and apparatus, namely, filtering machines, chemical processing apparatus, and apparatus for use in measuring, analyzing, or simulating fuel economy and emissions of internal combustion engines