Picard Industries has released the USB Quad aperture shutter system for blocking of multiple beams. It is supplied with four independently controlled pivoting-paddle USB shutters, 3-m USB cables, an externally powered hub and a custom application software program that runs on any standard PC under Windows XP/Vista. It provides a self-powered method of beam path shutter control and is hot-pluggable. Red/green status indicators on the panel reveal whether the shutter is properly connected to the hub and whether it is open or closed. The shutter button is clicked with the mouse to toggle from open to closed. When power is lost or disconnected, the shutter automatically closes. The system has a clear beam aperture of 19 mm.