1Small and compact, easy and portable to carry. 2Easy to use, just plug in the phone card and power on. 3Enhanced wireless signals for good performance. 4Builtin 35db sensitivity microphone, support two ways intercom. 5Concealed earphones are suitable for criminal investigation.Features:Small and compact, easy and portable to carry. Easy to use, just plug in the phone card and power on. Enhanced wireless signals for good performance. Concealed earphones are suitable for criminal investigation. Built-in 35db sensitivity microphone, support two ways intercom. Specification: Condition: Material: ABSColor: Yellow Card Size: 85 * 50 * 4.5mm Battery Capacity: 350mah Distance between GSM card signal and earphone: 40cm~60cm/15.7-23.6in Talk Time: 3~4 hours Headphone Battery Time: 6~7 hours Package Weight: Approx. 66g/2.3oz Package List: 1 * GSM Card 1 * USB Charging Cable 1 * A680 In-ear Headphones 2 * 337A Button Battery