Humboldt® Crack Monitor

Crack Monitor consists of two overlapping acrylic plates. One plate is white with a black millimeter grid; the other is transparent with red cross-hairs centered over the grid. Once the Monitor is secured with epoxy or screws across a crack, the cross-hairs shift vertically or horizontally on the grid, making crack movement easily visible and traceable. Can be fixed to the surface with screws or adhesive (not included). Comes complete with instructions and record sheet.