The Sena ACS10 is a Bluetooth communication system designed specifically for the Arai Contour-X motorcycle helmet. The discrete ACS10 headset consists of HD Speakers, a microphone, three-button control, and a battery, which are easily installed into the helmet. The ASC10 was designed for the exact interior recesses of the Contour-X, allowing for the perfect fit., The ACS10 provides high quality sound with Sena*s outstanding HD speakers. The HD speakers offer a marked increase in bass and audio clarity for music, intercom conversation, phone calls and more. In addition to HD Speakers the ACS10 also features Sena*s Advanced Noise Control* technology, which filters out wind and white noise in order to deliver crystal clear audio, The ACS10 allows for four-way Bluetooth intercom with a working distance up to 1.6 km (1.0 mi). Riders can also pair their smartphone in order to hear turn-by-turn GPS directions, listen to music, or even take a call...all from within their Arai Contour-X helmet, Link the ACS10 with the Sena Utility app to control many of the device*s functions from your fingertips, General, Operating temperature: -10?C * 55?C (14?F * 131?F), Talk time: up to 10 hours, Charging temperature: 0?C * 45?C (32?F * 113?F), Main module: 77 mm x 68 mm x 58 mm (3" x 2-11/16" x 2-5/16"), Wired Microphone: length 200 mm, Wire between speakers: length 100 mm, Speaker driver unit: 40 mm * thickness 7.2 mm, Intercom, Working distance: up to 1.6 kilometers (1.0 mile) in open terrain, Supports up to 4 riders, Battery, Talk time: 10 hours, Charging Time: 2.5 hours, 2 built-in 300 mAh lithium polymer battery