To complete repairs of a Fluke 23 I now only require some "1500 V surge protectors". That's what the BOM on the Fluke 70 series service manual calls them. Though on the 23 model one of them is actually 2 in series.
These are red, about 5mm dia x 4mm. markings are
H NI
1399They look like old Harris or GE MOV's.
The other one is yellow, 8x8x5mm, has a sawn slit half way through it and has markings
MDC
1-2KV 9143Any clues where to get similar ones at least? Farnell, Digikey and RS don't appear to go that high in voltage choices.