O2 (UK) sale units, and with handset manufacturers, such as Apple and Samsung, to enable NFC technology on all future devices. On 23 February 2011, O2 announced it would launch a "second phase" for O2 Money, by discontinuing its branded cash cards in favour of a "mobile wallet" application for Android and iOS devices. The application would use NFC technology embedded in a phone to access money. It was announced on 9 January 2014 that the O2 wallet service would close on 31 March 2014. The BT Cellnet consumer brand was renamed O – the chemical symbol for an oxygen molecule –
O2 (UK) certified with the Carbon Trust Standard in recognition of its commitment to reduce its carbon footprint. O2 attained the standard after saving 47,000 tonnes of carbon over the previous three years through its energy efficiency measures, including a £1.4 million distribution of smart metering technology across the company's cell sites, offices and retail stores, and upgrades to more energy efficient systems across its mobile phone network. In addition to distributing energy efficient LED lighting and boiler system controls, the company was also able to reduce energy use by removing air conditioning units from some of its cell sites and reducing