DESC: The E250 is a 2.5 GHz accessory handset designed for use with AT&Ts E2525 and E2555 expandable phone systems. It operates on the 2.4 GHz band and employs frequency-hopping digital spread spectrum technology to provide a clear, accurate signal with less interference. Caller ID/call waiting compatible, the E250 has a 50-number caller ID memory, while a 50-number phone directory is provided to help you keep track of important phone numbers.