In article ,
Eeyore wrote:

My best bet however is to try several 'heads' from my driver and see which
'locks
in' best. It's often VERY obvious !

I tried Phillips 0 and 1, as well as Pozidrive 0 and 1, on some Kenwood
and Icom case screws. On the Kenwood, all 4 bits felt about the same!
On the Icom, the PZ1 felt much more secure.

The Icom screw heads have a small dimple where the PZ "X" might be.
Since they are somewhat small screws, I wonder if the dimple is an
abbreviated symbol for Pozidrive?

Fred