The Inovonics EE1210W includes a built-in, side mounted magnetic reed switch, with a magnet that supports a 5/8" inch gap.

All you need is a receiver to alert your control equipment. If you are using a Castle Euro panel you can use the dedicated EUR-037R; alternatively you can use a universal 4, 16 or 32 channel receiver which provides outputs which can wire to any alarm panel. Coupled with the ES1266 Shock Sensor you can design a bespoke solution to any problem, be it fuel theft or void property.