The Avongard Corner Tell-Tale monitors horizontal and vertical movement across a crack in a corner. 

Specifications & Applications:
The Tell-Tale is hinged enabling it to be used in internal corners of angles between 70 and 180 degrees. 
Monitors both internal and external corners. 
Avongard Tell-Tales are precision gauges that consist of two plates which overlap for a part of their length. The bottom plate is calibrated in millimetres and the top plate is transparent and marked with a hairline cursor in the form of a cross. 
Fix using screws and adhesive (not included but available as accessories). 
Supplied with full instructions and Crack Record 

Use singly
To monitor two dimensional movement. 

Use in pairs
To monitor three dimensional movement. 
 
Floors & Ceilings
Re-configure the Tell-Tale components to monitor cracks between ceilings and walls or floors and walls.