4 Pack of 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.