2 Pack SainSonic GX-30 3D Glasses Active Shutter 144Hz Rechargeable for Universal DLP-Link Ready Projectors, BenQ, Optoma, Dell, Mitsubishi, Samsung, Acer, Vivitek, NEC, Sharp, ViewSonic - Black Revolutionary Technology - With most advanced 144Hz technology, it perfectly match the 144Hz DLP-Link projectors with the logo of 3D DLP Ready , offering more lifelike and amazing 3D viewing effect, and it is also compatible with previous generation projection technology. High Quality Transmission  Data is sent seamlessly, in millisecond response time, by the projector in between video frames to create Stereoscopic 3D images with no flickering; no emitter is required and the receiving distance is long with the maximum distance of 8m. Practical and User-friendly Design  Framed with ABS+PC material, it is portable and lightweight, making it very comfortable to wear even for a long time. The stable high quality LCD lenses will protect you from eyestrain. Environmentally Friendly Consumption  With built-in rechargeable battery and micro USB port, the 3D glasses can be recharged with micro USB cable. 3 hours recharging provides 50 hours operation, and 180 days under Sleep Mode. Automatic Power Off Function - When the 3D projector is powered off or not synchronized with 3D signals, the 3D glasses will be powered off automatically after 30 seconds.