Leitz Router Bit, Odd Shank Size?

[gazza]

Hi, i recently got a leitz router bit 2nd hand that i intended to use for trenching on strings.
When i tried to put it in my router i realized the shank is slightly smaller than the standard shank, its slightly under 11.5mm.
I cant seem to find anything on the size of this shank but when i look on the leitz site it does a lot of cnc bits.
So my question is, is this a bit for a cnc machine.

photos attached if you want to see it

Thanks for any replies!!