Is this a varistor?

[ElektroQuark]

275V?
And that 4 stands for...?

[Gyro]

It could be... but I'm not sure I'd stake my life on it without seeing exactly where it lives. 

If it is a 275V VDR then comparing it's physical size against RS, Farnell, etc. offerings would give a reasonable indication of its energy rating.

[Jeroen3]

Show where it is from.

[ElektroQuark]

I don't know. I have found a bunch of them in a drawer.
I think they will go to the bin.

[T3sl4co1l]

Do you have a capacitance meter?  What does it measure?

There is nothing printed on the other side?

Tim

[ElektroQuark]

89pF
Resistance measures more than 100 MOhm.
No, there isn't.

[Gyro]

Those figures do sound consitent with it being a Varistor.

There's nothing in the markings that is consistent with a capacitor in the 80-100pF range and it is also a bit too resistive for a capacitor. My other thought was that it might be a useful thermistor but that's gone out of the window too.

[ElektroQuark]

Any thoughts about the 4?

[ElektroQuark]

Found!

It's a Harris (now Littlefuse) V275LA4 model varistor. CLICK!

Thank you!