Testing conducted by Apple in September 2010 using preproduction 1.86GHz Intel Core 2 Duobased 13-inch MacBook Air units and preproduction 1.4GHz Intel Core 2 Duobased 11-inch MacBook Air units. The wireless productivity test measures battery life by wirelessly browsing 25 popular websites with display brightness set to 50%. Standby testing conducted by Apple in September 2010 using preproduction 1.86GHz and 2.13GHz Intel Core 2 Duobased 13-inch MacBook Air units as well as preproduction 1.4GHz and 1.6GHz Intel Core 2 Duobased 11-inch MacBook Air units. The standby test measures battery life by allowing a system, connected to a wireless network, to enter deep sleep mode with Safari and Mail applications launched and all system settings left at default.