Don't use a screwdriver on the beach, parks are where I use it, there are no potholes to worry about the grass dying, slice the sod, probe to get the depth of the target then recover it.3/4 of my detecting years were with no pin-pointer... and JFYI... I have and will always use a scoop.
I have tried just about every digging tool made on earth... in fact i cannot think of many i haven't.... from antique to modern sprinkler shovels and everything in between... i have invented half a dozen myself and helped in the development of a line of stainless scoops that are bar none to anything out there.
With all this jibber jabber I can say that even when doing / working with ordinance removal ... the smallest item ever incorporated into tools of the trade... by me or anyone else was a large knife.
Look i commend you all who have retrieved things with a screwdriver.
Personally i would never even try it.
If they said "no digging allowed"... i would not even metal detect it... so I have no need.
Nor would i even risk damage to anything i was attempting to retrieve with one.
Just me.
And rest assured ... I can tell you... I am in the treasure state... metal detecting capitol of the World....
And no one round here ever heard of such folly.
The man who used to make and sell these sold a lot of them, the 2 sizes are 7/8" and 1 1/4 inch.