1、COMPACT AND PORTABLE: GSM spy earphone is so small and loud that outsiders can't tell you're wearing this A808 headset for covert communication. 2、AUTOMATIC CALL CONNECTION: GSM invisible mini earpiece automatically connects calls and then transmits the call sound to the A808 headset in real time. 3、USES CELL PHONE SIGNAL: GSM mini spy earphone uses a cell phone signal, so you can talk like you're answering a call anywhere there's a cell phone signal. 4、MINI WIRELESS INDUCTION RECEIVER: GSM wireless mini earpiece is a miniature mini wireless induction receiver that converts sound signals by electromagnetic induction. 5、WIDELY USED: Widely used in many sectors, you can hear the voice of the person from the other side and the person on the other side can hear you. Item Type: GSM Wireless Mini Earpiece Material: ABS A808 Headphones: Length: Approx. 12mm/0.5in, Width: Approx. 7mm/0.3in Applicable Battery: 1 x 337 (SR416SW) 15mAh Button Cell (With 2 x Matching Battery) Always Working Time: 6 Hours A808 To GSM Module Distance: Approx. 40cm/15.7in GSM Module: Length: Approx. 4.5cm/1.8in, Width: Approx. 3cm/1.2in, Height: Approx. 1.1cm/0.4in Polymer Battery: 1 x 650mah Lithium Battery (Built In) Frequency Band: GSM 2G (900/1800MHz) 1 x GSM Module 1 x Headset 2 x Battery 1 x Earphone Storage Box 1 x Storage Box