Abstract: An apparatus for mounting a device for determining the position of a sliding sash door in a laboratory fume hood in the track of the sash door. This apparatus securely and permanently mounts the sensing means in the track even after exposure to corrosive and noxious chemicals such as MEK. This apparatus is thin enough to not to interfere with the operation of the sash door yet rigid enough to protect the sensing means. The apparatus includes a PVC base having a generally "I" shaped cross section with two recesses formed by two end portions and a middle portion of the base. The sensing means is located in one of these recesses and is secured therein by a first adhesive means. The PVC base and sensing means are attached to the track of the fume hood by a second adhesive means located in the other recess in the base. Both adhesive means are comprised of a high performance acrylic adhesive which is splash resistant to MEK.