Most professional LBY-3A roof separation indicator LBY-3A roof separation indicator is to monitor the separation of roof rock displacement amount generated by special equipment used to monitor the monitor roof displacement (separation wall rock) volume, avoid roof (country rock) treating collapse. LBY-3A roof separation indicator is mainly applied to the use of anchors, anchor supporting tunnel roof and the need to measure the displacement of the working face roof. Determining the bolt provided for the coal engineering and technical personnel and staff to detect length, tensile strength, is to understand the use of anchors, rational, scientific basis for economic anchor. Product Features: Roof separation indicator with high sensitivity, visual display, greatly reducing the visual error.