Abstract: A device to monitor the mounting and bearing integrity of a wheel mounted on an axle where a multiplicity of studs are used each having retainers therefore. A follower of generally dielectric material and having an electrical conductor is biased against the side of the wheel. An electrical contact maintains contact with the follower periphery and is relatively movable between the dielectric periphery and the conductor located in the periphery. The first electrical contact is fixed to the vehicle wheel. Monitor means indicates the electrical connection of the electrical contact and the follower conductor as an indication of the movement of the wheel from its previously fixed position on an axle.

Abstract: A pressure monitor for an enclosed body possessing an internal pressure differential utilizing a chamber having a piston disposed for travel therewithin. The piston includes a transversely mounted electrical conductor which forms an electrical bridge with a pair of contacts disposed on either side of the piston. A monitor means electrically connects between the pair of contacts to indicate the internal pressure of the enclosed body.