W53H VoIP SIP DECT handset, 1.8 inch colour TFT LCD, HD audio, 3.5mm headset jack, lithium-ion battery, for use with SKU #W60B, SKU #W53P, SKU #W60P or SKU #W80B. TECHNICAL NOTE: The W53H handset requires firmware version 88.83.0.90.rom or newer in order to pair and work with the W80DM base station in a multi-cell environment.