"Accessory PBX Panasonic KX-NSM710W, 10-Channel SIP Extension Activation Key (10 SIP Extension) 10-Channel SIP Extension Activation Key (10 SIP Extension). For KX-NS500/1000 "
Accessory PBX Panasonic KX-NSM710W, 10-Channel SIP Extension Activation Key (10 SIP Extension) 10-Channel SIP Extension Activation Key (10 SIP Extension). For KX-NS500/1000