Universal Active 3D glasses Optoma ZC501 with DLP-Link technology (original, full compatibility), for DLP projectors Optoma BenQ Acer Viewsonic JmGO XGIMI OBI DANGBEI. Optoma ZC501 3D Glasses for DLP Projectors Specifications: 3D Glasses Type: DLP-LINK Shutter Frequency96Hz/100Hz/120Hz/144Hz Wide Viewing Angle 178 Contrast: 1000:1(200) Polymer lithium Battery Working Time - 40 5 hours Appearance: Color Black/Red, Battery Power Button x1/LED Indicator x1/Charging Indicator x1 Battery: Rechargeable Battery (Please charge for at least 4 hours for the first time.) Sync Method: DLP Link Charging Method: Micro-USB Charging Battery Working Time: More than 40 hours Accessories: Package Contents: 3D Glasses/USB Cable/Lens Cloth/Carrying Bag/Manual Instructions for 3D glasses: Charging time: About 2-3 hours (the first time at least 4 hours) Power on: Press the power button, the green LED light flashes once, means the glasses have been turned on. Power off: Press the power button for 3 seconds, the green LED light flashes three times. Standby state: Within 5 seconds without 3D signal, the glasses will automatically enter standby mode, the green LED light flashes every 5 seconds. USB charging: The red indicator light is on when charging, and it turns off after it has been fully charged. Low battery mode: When the 3D glasses are low in power, the green LED light flashes five times continuously, then twice every 10 seconds. It means you need to charge the glasses. To use the 3D glasses, the first press will turn it on, the second press changes right/left to adjust the 3D effect on the glasses until the image is correct. (You need to choose 3D effect up/down or left/right when playing video on the projector.)