If it doesn't say that it supports Vista then you have to proceed on the
assumption that it does not. How else can you do it? The manufacturer
would say so if it did because that would be a selling point. Anyway, it
was released on June 1, 2005, 18 months before Vista came out. If the
manufacturer did not write a new driver since then, it will not work.
Cnet reviewed it on 7/13/05:
http://reviews.cnet.com/mice/gyration-go-2-4/4505-3148_7-31428447.html
The supported operating systems are listed at the end of the specs:
http://reviews.cnet.com/mice/gyration-go-2-4/4507-3148_7-31428447.html?tag=sub
The manufacturer's support page does not list any downloads so there must
not be any driver updates.
http://www.gyration.com/t-DownLoads.aspx
The Windows Vista Hardware Compatibility List (filtered on Gyration input
devices) is here:
http://winqual.microsoft.com/HCL/ProductList.aspx?m=v&g=d&cid=400&f=86p
There is simply no indication that the device will work with Vista. Other
than that you can try it but I wouldn't buy one just to find out.