Zoukfox 144Hz 3D IR Active Rechargeable Shutter Glasses for Acer ViewSonic BenQ Vivitek Optoma 3D DLP-Link Ready Projector, Black (1 Pack) Portable,Light Weight and Comfortable for long time wearing. Recharge with micro USB cable,glasses can work for approximately 20-hours when full charge. Simple One Button Operation for Turn On/Off, L/R Switch Battery life check. Wider vision making the viewing experience Superior. Indicator Light for showing Battery status.