"Hehuanquan" is a social application launched by Beijing Mobile, which mainly aims at users in Beijing and provides various functions including social, entertainment and life services. Circle can help users find "circle friends" around them, establish interest communities in different fields, share their lives interactively online, and provide activities such as point redemption and punching cards to increase user interaction, participation and gain feelings. Users can download, install and use ringtones on their mobile phones.