The 2747A-L From Interlogix is a high-security magnetic contact with triple biased reeds are highly resistant to defeat by an external magnet. For added security, magnetic field tamper and pry tamper are standard features. Each 2700 contact and actuation magnet set is factory compensated for the effects of steel. The 2700 Series is designed for protecting high-security facilities such as airports, warehouses, manufacturing plants, banks, and military bases. The Sentrol high-performance magnetic contacts have been designed to facilitate installation and ensure durability and dependability. Most are conservatively rated at 10,000,000 cycles, guaranteeing a long life. Every reed connection is hand soldered and each magnetic contact is tested before they leave the factory, 100% of the time. Reed's legs are plated with rhodium or ruthenium and hermetically sealed in dry nitrogen. This offers superior protection against sticking and provides a moisture-free environment, therefore, preventing corrosion.