Most efficient video recorder: Start recording as soon as Q2 detects somebody motion; Build-in PIR detector: Once it is activated, Q2 will start to record 30 seconds video, then turns to standby mode to wait next trigger; Support SD card: 4 - 32GB, auto overwrites; Record audio: Up to 10 meters effective record range; Replay video files on computer: Via USB cable, plug-and-play;Easy DIY installation, free use-cost.