Novice with an unknown Fuze

[bullstreetboy]

Guys

I'm new to this so possibly a naïve question

I have what appears to be a proximity fuse:-

It looks like a MK 53 but a metal cone - not plastic.

Markings are :- No 207.I.R.O.F.(B).1940

Left hand thread with a brass base with a scale marked 0-30 and then safe.

3 holes on the base in a "V" and then a larger hole at 11 O'clock

Any thoughts much appreciated.

 

[Weasel]

Hi Bullstreetboy,
The No207 fuze was a mechanical time fuze used on the 3.7" Anti Aircraft rounds.
Best regards Weasel.