Released in September 2001, the Ericsson T66 mobile telephone was the smallest mobile phone to be released by Ericsson Mobile Communications. It surpassed the tiny Nokia 8210 in smallness and weight at the time. After Ericsson merged with Sony Corporation in 2001 to manufacture mobile phones, the T66's body and color were changed, and it was renamed the T600. Production of the T66 and its predecessor Sony-Ericsson T600 has been discontinued. The T66 was compatible with GSM 900/1800/1900 mobile phone networks.