With a projection range of 0.4 to 3.4 metres, the Optoma W309ST short-throw projector supports projection screen sizes of 0.91m to 7.7m. Add that to the high contrast ratio and high brightness (3,800 lumen) and clear imaging is guaranteed. What's more, this premium projector offers full 3D support and features a built-in 10W speaker, making it ideal for both business presentations and home entertainment. Other Features The W309ST has been fitted with HDMI, VGA and composite inputs, giving you ample options when it comes to hooking up an input source. You also get an RS232 port, an Eco AV-mute function for blanking the screen and saving power, and a built-in Kensington lock slot plus a password protected interface for maximum peace of mind when installing the projector in public spaces.