NIER iRock Portable Wireless Bluetooth 4.1 Speakers, Aluminum Housing, 10W4 total 40W with EQ Function (Silver) 1, Built-in 4 pieces 10W speaker total 40W which brings really clear and powerful sound. 2, 2600mAh High capacity rechargeable battery enables a long-lasting playing time up to 8 hours. 3, Latest Bluetooth v.4.1 technology which is more stable and compatible. 4, Smart EQ button to select different sound effect such as Low, Middle, High pitch. 5, Support external audio AUX input and also can be used as an external power bank with USB output