[Connect to 4 Riders] When 4 machines are connected, 4 referees can talk at the same time. The maximum distance between each machine is 700 meters for each 2 person, and the total distance can reach about 2000 meters. If 2 machines are connected, the intercom distance can reach 1200 meters for V4Cplus referee bluetooth intercom, referee communication system. | [Multi-function] EJEAS V4Cplus referee communication system can also be used as a motorcycle bluetooth helmet intercom, connect to mobile phones, GPS, MP3 etc, answer phone calls automatically, listen to music and navigation. Voice assistant helps to free hands and ensure a safety journey, FM informs the latest traffic conditions. | [Large Capacity Battery & IP65 Waterproof] With a large capacity battery of 750mAh, running for 12 hours, and the standby time can be up to 450 hours. The professional referee Bluetooth headset V4Cplus can be used in various situations, such as match, training, cycling, skiing, construction sites, etc. | [CVC Noise Reduction & Warranty] V4Cplus Bluetooth referee communication system can reduce the background noise of input and output audio signals, effectively eliminate more than 90% of the environmental noise, the voice quality will not be affected even at 120 km/h. We offer a 12-month warranty, if you have any questions about V4Cplus Bluetooth referee intercom communication system, you can contact us at any time, we will give you a satisfactory answer within 24 hours. | [For Advice] V4Cplus is mainly made for professional coaches and referees for different training and match needs, and it can also be used in motorcycle area, as a motorcycle Bluetooth helmet intercom, V4Cplus is different with V4Plus in accessories, V4Cplus referee intercom has a single-ear headphone, and an armbag to bind on twist or arm. You could choose a suitable one between this two version.