Help Identifying Spark Plugs

[MontyC]

Found these 4 spark plugs in the workshop, no idea what they are from any ideas?

[eccles]

They remind me of aircraft ones.

[GuitarTech]

Defo aircraft plugs, no idea what engine. What I can tell you is that they're NOT from either a Gypsy Major or any Lyccoming engine, as they're the only engine types I have changed plugs on.

[guindilias]

Military spec generators/other IC kit use the same type of plug as well - could be from anything, really!

[MontyC]

Thankyou for your help. I did wonder if they were aircraft plugs but was unsure.