Built for communicating with another rider, the SF2 Bluetooth Communication System provides 2-way intercom communication up to 800 m (880 yards) in open terrain. The SF2 also lets riders enjoy smartphone connectivity allowing for music streaming, taking and making phone calls, and hearing turn-by-turn GPS directions. Plus, with the Audio Overlay feature, riders can simultaneously listen to music and use the intercom so you are never disconnected. Plus, with the Quick Charging capabilities, you will be ready to start your ride in no time.Working distance of up to 800m (880 yds) in open terrain.30 minutes Quick Charge equals 4 hours intercom use.Lithium Polymer Battery for long life use.HD Voice enabled for high-quality phone call audio.Each SF2 comes with one standard and one HD speaker set. The HD speakers will take your ride to the next level with louder, clearer quality audio. The standard speakers are a bit smaller in size and may be a more comfortable choice for some riders. The S