Reed sensitivity on door/window sensors

I noticed 2gig door/window sensors have a specification like this:

Reed sensitivity: 0.625 in. minimum gap, 0.85 in. typical

What does that mean, 0.625" minimum gap - that confuses me since the installation instructions say “Mount the magnet no more than 0.4 in. away from the sensor.”

Yeah, that is very confusing. I believe what it means is that the reed sensor will trip when the magnet is between .625 and .85 in. away from the sensor. It is recommended that the magnet be no more than .4 in. away from the sensor to reduce false alarms and false opening. I’m checking with 2GIG to verify and I’ll update this thread as soon as I get confirmation.

I’m mostly curious because of the recessed door/window sensor:

In that situation, it would be hard to create a minimum gap of .625" - they’re basically on top of one another when the door is closed. :slight_smile: I think your explanation makes more sense regarding the distance required for the sensor to trip.