Ok I have a slightly used "Pro Motorcar Products" ETG Mini Paint thickness Gauge, Been using it a while, but since I am not detailing as much I am not using it at all now a days. It is in GREAT condition, and takes Accurate readings.
Here is a Product description page for it.
ETG-MINI Pocket Size Electronic Paint Thickness Gauge
List price is $370,
$250 OBO This is a discount PTG, but works just as well as the more expensive ones.
Here are some pics if you wanted more info just ask.