Is this printer supported

Hi Guys,

Here is a link for a printer one of our clients was thinking of purchasing. I just want to be sure its supported:

http://www.uline.com/Product/Detail/...hermal-Printer

The reason im asking is in compatibility it says its not compatible with UPS worldship or FedEx software. But the GK420 is in your supported printers list. Please let me know if its supported so i can give the client the go ahead in purchasing it. Thanks