Magnets for use with our Reed Switches. Approximate sizes 18 x 3 x 3mm. 25 x 5 x 5mm. In the table below the distance in mm is that when the reed just operates & just releases when the wide face of the reed is parallel to a long face of the magnet & is measured from the centre of the reed to the nearest face of the magnet. In practice reduce the operate distance & increase the release distance by 25 to ensure reliable operation. Magnet Large Standard Compact Miniature Operate distance 22mm 19mm 26mm Release distance 36mm 29mm 36mm Magnet Small Standard Compact Miniature Operate distance 6mm 5mm 10mm Release distance 12mm 9mm 15mm