Metal 3-Post Magnet with Adhesive. 1 3/4" x 1/2". Magnet/Metal/Nickel Plating. Surface Gauss rating: 2500. Gauss rating is magnetic strength rating. The higher the number the stronger it is. This magnet should not be used with a pacemaker. All JDS magnets have adequate strength to be used as badge attachments. Foam tape adhesive is on the side without the magnet.