Abstract: An improved sensor and system of attaching sensors to their associated equipment, tooling or product. This attachment device provides stability of the sensor, quick removal and installation and a definite seating position thus providing a consistent reference point. The sensor holding system combines a flange on the sensor with a groove for the engagement of pre-loaded spring biased balls, and an outer housing that incorporates an opposing flange for seating the sensor and a ring of radially inwardly biased pre-loaded balls to engage the circumferential groove in the sensors. The diameter of the outer housing is determined by the sensor body but is kept as small as practical.