Standby time: 240 hours Continuous call (music playing): 8 hours Charging time: 3 hours Waterproof: yes FM radio: support Bluetooth version: 3.0 Product name: V4C headset Intercom certification: CE, FCC, Rohs Bluetooth intercom V4C intercom Function: 1. Communicate with the main referee and assistant referee during a soccer match. It can also be used for motorcyclists, skiing enthusiasts, construction and mining, fire brigade personnel, traffic police etc.2. Main switch available CSR BC5 Bluetooth diagram;3. Advanced Bluetooth A2DP and EDR function available; 4. Powerful stereo music/audio available (mobile phone/MP3/GPS with A2DP for transmission); 5. DSP noise reduction function;6. 500mA lithium polymer battery; Product Name: V4C Headset Standby Time: 240 Hours Continuous Call (Music Playing) : 8 Hours Charging Time: 3 Hours Waterproof: Yes FM Radio: Support Bluetooth Version: 3.0 Intercom Certification: CE , FCC , Rohs More Pictures for Football Referee Headset Waterproof Bluetooth V4C Intercom Intercom: Accessories for V4C referee intercom headset: V4C Bluetooth intercoms x 1 Referee coach headset x 1 (Optional hook type or ear type) USB charger cable x 1 Headband (inserted into the intercom) x 1 User manual x 11200M 4 user to speak at the same time Intercom Football Referee Headset Full Duplex Bluetooth Intercom V4C Intercom Football Referee Headset Referee Talking Use New Kit 1200m Full Duplex Bluetooth Intercom - Bluetooth Support 4 User to Talk at the Same Time. Communicate with the Head Referee and Assistant Referee during a Football Match .It can also be used for motorcyclists, skiing enthusiasts, construction and mining workers, fire brigade workers, traffic police etc. Note: Since the factory has updated V6 new version now, they cannot connect with V4 more than 2 pcs, so we do not recommend connecting with different models, if you want to talk to more than 2 people, please buy the same MODELZ V4 to use. Thanks for knowing this.(V4 can't connect with new V6)