Grandstream dp722 dect, 10 sip, 10 lines, silver // supports a range of up to 350 meters outdoors and 50 meters indoors when used with the dp752 (300 meters outdoors when used with dp750) 1.8 inch (128x160) color lcd with 2 programmable soft keys offers 20 hours talk time and 250 hours standby time supports up to 10 sip accounts and 10 lines per handset as well as 3-way conferencing push-to-talk via a configurable button seamless 1-touch door control with grandstream’s gds series of facility access devices hd audio on the speakerphone, handset, and headset jack software and firmware updates over-the-air https //www.grandstream.com/products/ip-voice-telephony/dect-cordless/product/dp722