The RTF is a jointmeter used to measure the displacement of cracks in structures or rock masses. The sensor is housed in a rugged waterproof enclosure which is fitted at one end with a spring-loaded rod resting against the reference surface located on the opposite side of the discontinuity. Supplied with an installation template, the RTF is available in uniaxial (RTF 1D) and triaxial (RTF 3D) versions