Third party focus drift control

[cathale]

Dear all,
since I had the problem with multiple microscopes I am trying to compile a list of all vendors for third party focus drift control solutions
Here is what I got. Any other ideas would be welcome:

1) MadCityLabs C-focus system which can be controlled by micromanager or labview. http://www.madcitylabs.com/cfocus.html
2) Physik Instrumente offer a focus drift control as part of their P-737 pifoc specimen focussing z-stages http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=201546

Cheers,
Chaitanya