XGIMI DLP Link 3D Glasses - Rechargeable Active Shutter Glasses for DLP 3D Ready Projector (Color Blue) Rechargeable---- Built in rechargeable battery for added convenience. Can be recharged with included USB cable. Working hours up to 20h after 2.5h full charge. Comfortable---- Anti-interference humanity electronic design and convenient operation button for comfortable using experience. Smart Synchronization---- No emitter is required. Adopt high speed LCD lenses, millisecond response time protect you from liable eyestrain. Great 3D Experience---- With newest active shutter technology, high definition and no flickering, offer fluent, bright and sharp 3D experience. Compatibility---- Designed for XGIMI projector