GMYLE 144 Hz 3D Active Shutter Glasses for DLP-Link Projector with Rechargeable Built-in Battery (Size S, 1 Glasses) 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.