I used the same clear round 22mm counters for my Casualty markers, but i cant remember the name of the Company.
Here you have the objective markers and as you can see there are 10 of them, but only one has the objective painted on the underside.
Here you have the sound markers, and they are used when people shoot or break door or shout,
sound attracts zombies you now ;)
And here are some useful counters when you have locked doors, broken doors and broken windows.
Hope its can be of use to all you zombie games out there :)