What is this toroid looking component?

[geratheg]

I initially picked this up from a hacker space assuming it's a toroid, and could not find any specs for it.
It has 4 terminals, which I assumed would be connected to each other in pairs.
Measuring resistances didn't help, they all showed some resistance about 1.5k ohms.

What can this component be?
The number of the component reads NA-25 0125

I googled it, but I'm not sure what I'm looking for.

 

[(*steve*)]

I suspect it's a hall effect senor in a gap in a toroid. It will be used to measure current.

Often such a sensor is inside a chip which converts the hall voltage into a logic signal or otherwise. If all of these leads have approximately the same resistance to each other then it may just be a naked sensor.

 

[geratheg]

Thanks for the response.

Two of the leads only had about 500 ohms, everything else I tested was between 1.3 - 2k+ ohms.

 

[abuhafss]

Yes, Steve is right. It is a Hall-Effect Current Sensor.

http://www.farnell.com/datasheets/1359198.pdf