The GLSL hole detector from Fiessler Elektronik scans the entire width of a test object simultaneously, allowing scanning speeds of up to 20 m/s to be achieved. The detectable hole size is infinitely adjustable by the operator. The hole detector is suitable for both opaque and translucent materials. The user can choose between 'static' and 'dynamic' operating modes using the operating mode selector button. For translucent materials, the hole detector must be switched to 'dynamic' mode. The quality check is carried out on moving parts. The 'static' operating mode can be used to inspect opaque materials. In this operating mode, quality control can also be carried out when the test object is stationary. The hole detector consists of a light transmitter and a light receiver and is made up of modular components. The transmitter emits an invisible, modulated infrared light band, while the receiver consists of a series of receiver elements and a signal amplifier and evaluation unit integrated in the housing. When a hole occurs, the output transistors conduct or the relay picks up. Optionally, the hole detector can determine over which receiver unit the hole is located. The defects can therefore be localized not only in the feed direction, but also perpendicular to it.