Black Smart Bluetooth Bone Conduction Glasses for cellphone,Prescription Glasses AOS patented full bone conduction (speaker + microphone) design; Bone conduction speaker efficiently provides clear voice signals in windy and noisy environments and reduces the risks of outside sound isolation such as car horn honking; Bone conduction microphone allow voice transmitted through nasal bone and reduces interference of environmental sound; Replacable lenses; included a pair of plano transparent lenses Bluetooth V4.0 supported; standby time up to 50 hours; talk time up to 2-4 hours; continuous music time up to 4-5 hours.