Pioneer released the LaserActive system which had a bay for various "PAC's" such as the Mega LD PAC and LD-ROM² PAC. The unit was 3D capable with the addition of the LaserActive 3D goggles (GOL-1) and the adapter (ADP-1). While the 3D hardware for these earlier video game systems is almost entirely in the hands of collectors it is still possible to play the games in 3D using emulators, for example using a Sega Dreamcast with a Sega Master System emulator in conjunction with a CRT television and a 3D system like the one found in The Ultimate 3-D Collection. In 1999–2000, a number of companies created stereoscopic LC shutter glasses kits for the Windows PCs which worked with application and games written for Direct3D and OpenGL 3D graphics APIs. These kits only worked with CRT computer displays and employed either VGA pass-through, VESA Stereo or proprietary interface for left–right synchronization. The most prominent example was the ELSA Revelator glasses, which worked exclusively in Nvidia cards through a proprietary interface based on VESA Stereo. Nvidia later bought the technology and used it in its stereo driver for Windows. The glasses kits came with driver software which intercepted API calls and effectively rendering the two views in sequence; this technique required twice the performance from the graphic card, so a high-end device was needed. Visual glitches were common, as many 3D game engines relied on 2D effects which were rendered at the incorrect depth, causing disorientation for the viewer. Very few CRT displays were able to support a 120 Hz refresh rate at common gaming resolutions of the time, so high-end CRT display was required for a flicker-free image; and even with a capable CRT monitor, many users reported flickering and headaches. These CRT kits were entirely incompatible with common LCD monitors which had very high pixel response times, unlike CRT displays. Moreover, the display market swiftly shifted to LCD monitors and most display makers ceased production of CRT monitors in early 2000s, which meant that PC glasses kits shortly fell into disuse and were reduced to a very niche market, requiring a purchase of a used high-end, big diagonal CRT monitor. SplitFish EyeFX 3D was a stereo 3D shutter glasses kit for the Sony PlayStation 2 released in 2005; it only supported standard-definition CRT TVs. The accessory included a pass-through cable for the PS2 gamepad; when activated, the attached accessory