Our stepper-motor driven shutters provide fast and accurate exposures and are ideal for microscopy and machine vision applications. The controller allows programmable control over the ex-posure time and the delay between trigger and shutter opening. The controller contains a three-position switch, which allows the shutter to manually open and close or be remotely controlled. RS-232, USB and TTL inputs can be used for remotely controlling the shutter. A TTL output line located in the rear panel of the controller allows for cascading the trigger input signal to another device. The interface software allows selection among three modes of operation: Fast, Soft and Variable Aperture (Neutral Density) Mode. The shutter can be configured to close and reopen repeatedly or loop for a specific number of cycles. The shutter consists of a single blade made of bare aluminum. The 25mm shutter can be mounted either through its C-Mount threads or via its 8-32 tapped hole at the base. The 35mm shutter uses T-mount threads for mounting.