A-Trend Helios 3D Voodoo 2
A lot like this Helios 3D Voodoo 2. Since they technically identical (i.e. 12MB) you can pair them to create a SLI set. SLI stands for Scan Line Interleave and doubles the rendering power as well as increasing the maximum resolution to 1024x768. Back in 1998 a Voodoo2 SLI-set was the fastest graphics setup you could have.
Back then with the original drivers you needed two identical branded cards to run in SLI. If you use the FastVoodoo2 drivers you can run a mismatched setup. You do have to have identical amount of RAM on both cards, mixing 8MB and 12MB cards won't work.