What is it?

...The Avongard Crack Monitor is a simple and effective gauge to measure the movement of cracks in brick, concrete, or masonry structures.

The Avongard Crack Monitor consists of two overlapping acrylic plates. One plate is white with a black millimeter grid, while the other is transparent with red crosshairs centered over the grid. Once the Crack Monitor is in position across a crack, the crosshairs shift vertically or horizontally on the grid if movement occurs,so that anyone can easily see and track crack movement .

Specifications