What deserves to be mentioned is the battery inside our head strap. Instead of using the 18650 cells, KIWI design battery strap adopts the Amprius industrial-rank cell 3200mAh x2 pieces. As a pioneer and the established leader in the production of high-energy-density lithium-ion batteries, Amprius makes the highest-energy-density Lithium-ion batteries in the World. It performs excellently in safety and quality. Definitely, it makes a higher cost, but we are confident to say that KIWI design makes the best battery head strap. Except for the quality control from the cell supplier, KIWI design also takes a high value on the testing. Especially on the thermal control. Even more than 4 hours of active gameplay with Quest 2 and our battery strap, the highest temperature near the "Meta" logo are always 42℃ below. And no worry about charging in the carry case, the temperature is even low about 33℃. Besides the safety guarantee, the 78% power conversion rate of the Amprius cell is much better than the market average working efficiency of 65%, and the lifespan of more than 2000 times charge and discharge. It adds about 2.5-4 hours (APP depends) of use time when fully charged. KIWI design always aims to be your trusted VR game companion, including providing our customers the price-worthing products.