Quantum3D Obsidian2 S-12 3Dfx Voodoo2 12MB 3D accelerator add-on card. Brand new in box, still sealed in factory shrink wrap. The shrink wrap has a small tear on the front of the box and a couple on the back and some writing on the plastic on one end of the box (see photos). Designed for Windows 95, 98 and NT 4.0 with Service Pack 3. Requires a 2D video card to operate. Two Voodoo2 video cards can be combined in SLI mode. See photos for additional information. One of the rarest of all 3dfx video cards. There are not many surviving samples, especially with the box, probably because Quantum3D video cards were some of the most expensive.IMPORTANT NOTES - READ CAREFULLY:The Quantum3D S-12 is different in several ways from the 3Dfx reference Voodoo2 design used by other manufacturers.The Quantum3D Voodoo2 uses proprietary connectors: a smaller SLI connector and a pass-through cable that uses a round connector on the card instead of a D-sub VGA connector so these only work in SLI mode with other Quantum3D Voodoo2 cards.Quantum3D is the only manufacturer that offered an AGP as well a PCI version of the Voodoo2 (PCI is the most common, AGP is rare). Because the card was offered in AGP, it was designed to operate at 66MHz vs 33MHz with a core/memory clock speed of 100MHz vs 90MHz (AGP spec), even though the PCI bus is limited to 33MHz. Every Quantum3D Obsidian2 S-12 box I have seen show this 66MHz information, even on PCI editions of the card.There is nothing on the box indicating whether this is a PCI or AGP card (the box has information listed for both). There may have been a sticker or label on the outside of the plastic wrap that has gone missing. Originally there must have been a way to identify which card was in the box, but there is no way to tell without opening it. As a collector, I preferred to keep it unopened as a display item and didn't care whether it was AGP or PCI. Just be aware that I DO NOT KNOW WHETHER IT IS AN AGP OR PCI CARD IN THE BOX and I make no claims regarding this.