This Flush mounted magnet contact can be used in security systems up to and including grade 1 and environmental class II as specified in EN50131-1 and is compliant with EN50131-2-6. It operates as a normally closed circuit going open when the magnet is removed. This contact is not suitable for ferrous surfaces. Features Quick Fit Flush Magnetic Contact Body 19(dia) x 15 – Face plate 35 x 22mm 5 Terminal Operating Gap – 20mm EN50131-2-6 Grade 1 Environmental Class II