The JM is a jointmeter used for monitoring displacement between concrete lifts in concrete dams. Rugged built, it consists of a vibrating wire displacement transducer inside a telescopic stainless steel housing. Easy to install, and extremely stable and reliable, it is also used to monitor separation of shotcrete from a rock face in tunnel walls as well as determining crack and joint movement in structures.

Datasheet: 

JMS&JME-E5057C.pdf

Manual: 

E1057C-100406_JM Series.pdf