HSI Spot On Leverless Limit-Switches are designed to handle the most extreme operating environments. The four different Spot On models can sense farther, faster and last longer than the competition.
*SPOT ON WIRE COLOR DESIGNATIONS:
Black Wire = Common / Red Wire = Normally Closed / Blue Wire = Normally Open / Green Wire = Ground (steel housing only)
From 'Making Sense' Blog
Get Added Security with Door and Window Security Sensors
Door sensors, also known as entry point sensors, contact sensors, or window sensors make up the backbone of any security system. If a door or window gets opened or breached when the alarm is on, the sensor sends a signal to the main control panel, triggering an alarm. In the past, older door sensors only … Continued