Yealink EXP 55 extensionsmodul - suitable for Yealink SIP-T73U,

Yealink EXP 55 extensionsmodul suitable for Yealink SIP-T73U, Yealink SIP-T73W, Yealink SIP-T74U, Yealink SIP-T74W, Yealink SIP-T77U, Yealink SIP-T85W, Yealink SIP-T87W, Yealink SIP-T88V, Yealink SIP-T88V Pro, Yealink SIP-T88W, Yealink SIP-T88W Pro