Doosl® Bluetooth 4.0 ReceiverThe Doosl 2nd Gen Bluetooth V4.0 Receiver is special designed for the most devices with 3.5mm AUX port， such as car stereos， home stereos/speakers， headphones etc. Easy to use， just plug it into the audio devices mentioned above， and match the Bluetooth with your mobile phone. Safe， easy and hands-free product for you to listen to the music through your car stereo. It will make your traveling more relax and interesting. It is the optimal accessory for you while driving. Specifications Model: DSER102 Dimensions: 2.0*1.0*0.4 inches Bluetooth Version: V4.0 Bluetooth Range: Up to 30 feet Power Supply: inner 250mAh Li-Battery charging via Micro USB cable Compatibility: car stereos， home stereos/speakers， headphones etc. by 3.5mm stereo inlet socket Operation Time: up to 16 hours (built-in battery) music playback or continuous with Micro-USB charger Package includes 1 x Doosl® 2nd Gen Mini Bluetooth 4.0 Receiver1 x 3.5mm Plug 1 x Usage Manual