Function : Bluetooth audio: bluetooth 3.0. Maximum receiving distance of 15m. Bluetooth phone: clear voice, no echo, bluetooth voice navigation. Audio output: fidelity, subwoofer output, large output volume, acoustic reading learning Tf card player: insert tf card, it automatically turns to tf card player, supports mp3 format, acoustic reading learning. Control:human touch sensing Power and memory: automatically memorize the previous volume Active connection: open bluetooth speakers, automatically connect to previous device Built-in battery: 1000ma built-in rechargeable lithium battery which is environmental-friendly and energy-saving Long working hours: after a one-time full power recharge, can work for more than 10hours. Lighting for more than 2hours Insulation effect: 80 degrees above 2hrs; 58 degrees above 6hrs Cold preservation effect: 11 degrees below 6hrs Executive standard: gb9684-2011 Patent no: zl201520542633.5 Model: zkd-118 Cup cover: imported food grade abs Cup body: imported food grade 304 stainless steel Capacity:380ml