... , internal and external gr Mono-block depth gauges with a hook: Mono-block vernier. For depth, step, internal and external groove measurements ... measure ranges: 150mm, 200mm, 300mm, 500mm. Digital depth gauges with a hook: For depth, step, internal and external measurements. Manual power on ... . There are many different measure ranges: 150mm, 200mm, 300mm, 500mm. Depth Gauge