HD portable handheld A4 scanner $ 30.78 Image sensor: A4 color photoelectric sensor White balance: automatic Scanning resolution: 300dpi, 600dpi, 900DPI Storage format: JPEG/PDF optional Scanning range: A4 (216mm) Scanning speed: color 900DPI 12 seconds/page color 600DPI 8 seconds/page color 300DPI 3 seconds/page Extended memory: MicroSD/TF (1G-32GB) Transmission method: USB2.0 Power source: battery (No. 5 battery X2) Working mode: offline scan Automatic shutdown: automatically power off after 3 minutes of inactivity