Four Handset cordless telephone with Answering machine and dual keypadLink up to two smartphones via Bluetooth to make and receive Cell/smartphone calls anywhere in the house with link2cell handsets, no landline requiredHear who's Calling from across the room with talking Caller ID announcements in English and Spanish from the base unit and cordless handsetsEasily block up to 250 telemarketers, robocallers and other unwanted numbers with one-touch dedicated call block buttons on base unit and handsets.Other conveniences include dual keypad, full duplex speakerphone, power back-up operation, headset jack, baby monitor, silent mode, noise Reduction and Intelligent Eco modeVolume Control : 6-level. Frequency -1.9 GHz