Varistor

I've a varistor. Basically looks like a giant ceramic capacitor (that lovely beige colour about the size of a nickel) the markings are

B
103K
1KV
KCK

I can't remember where I got this but I'm fairly sure it's from the front end of a power supply.
Can anyone explain the markings fully? B looks like a tolerance rating. 103k is a resistance value?, 1KV is voltage obviously, no idea what KCK means.

Maruwa KCK Co Ltd
I believe this is an old part number.

Well don't I feel silly. Didn't even recongnize the markings, it's not a varistor it's just a cap. 10nF 10% 1KV cap.