SODIAL(R) 4x DLP- Link 3D Projector Active Shutter Rechargeable USB Glasses Wireless Ergonomic design, exquisite appearance. Low energy, low carbon and environmental protection. High permeability rate to ensure perfect quality. If the 3D glasses do not receive the sync signal, automatically turn off after 5 minutes.Long-lasting use. Signal transmission: Wireless communication with compatible 3D DLP-Link Projectors