The Yealink W77P SIP wireless phone system is ideal for use in busy environments. The powerful business system supports up to ten W57R handsets. Set consists of W57R handset and W70B base station DECT radio coverage up to 50 m indoors and 300 m outdoors Energy-saving ECO function IP54-rated durable handset Excellent HD audio quality Supports up to 10 SIP accounts and 20 simultaneous calls Fast charging and vibration alert