The Model 4350 Vibrating Wire Biaxial Stressmeter is designed to measure compressive stress changes in rock, salt, concrete or ice. Three or six Vibrating Wire sensors oriented at 60° intervals allow the principal stress changes to be measured in the plane perpendicular to the stressmeter axis. The stressmeter consists of a high strength steel cylinder which is grouted (or frozen, in the case of ice) into a BX (60 mm) size borehole.