Strain gauges are very commonly used in the market, but BoltSafe load sensors use a different kind of technology. They measure changes in the magnetic field using magnetoelastic technology. Because of this, BoltSafe sensors are more compact (low clearance) and are less expensive than strain gauges. The BoltSafe load sensors are specially designed to measure and monitor the bolt load in bolted joints. This enhances safety, makes joints more dependable and results in better control over bolted connections.
Because our sensors are used as washers, they are placed on the non-driven side of a bolted connection, preferably under a nut. The difference with strain gauges is that while tightening the bolt, the applied force results in a minor deformation of the BoltSafe washer; and then the sensor constantly measures changes in electrical resistance caused by these deformations. We use this data to determine the bolt load at any given moment.