The SE-38 First*Edge Sensor is an all-digital web sensor specifically designed or materials with varying opacities. Such voids, common with spun bond and loosely woven materials, are often difficult to detect with typical Infrared sensors, and nearly impossible to detect with air or ultrasound.

With its unique 180º foldback prism, the SE-38 is capable of detecting the first edge of a web and then ignoring any and all subsequent variations. It has a standard sensing gap of 50.8 mm (2 inches) and a control range of 43.2 mm (1.7 inches) delivering precise, versatile control for single-edge or center guiding applications.