This is an active shutter 3D glasses identify intelligently signals of all kinds of brands DLP technology projector with the widest compatibility. Innovative and fashionable design and fabrication processing eliminate electromagnetic interference the latest flicker free shutter 3D technology HD no flash no ghost shadow can wear under most common glasses or glasses for the myopia. High quality liquid crystal lens provide high contrast and clearness brightness and sharp 3D experience through lens. Auto power off function the glasses will power off automatically to save power when there is no synchronizing signal. Signal will realize intelligent synchronization when power on respond and show intelligently terminal operating frequency. Transmittance: 36% (TYP) field frequency: 120Hz contrast ratio: 1000:1 charging time: 2.5 hours stand-by time: 180 days operating time: 20 hours Bluetooth transmission characteristics receiving distance: 8M (max) receiving angle: up and down: ±35 degree left and right: ±55 degree temperature characteristic: operating temperature: 0~50 degree storage temperature: -30~70 degree.