The electronic Liquid Crystal glasses work with any PAL or NTSC CRT type TV's. For field sequential 3D DVDs. Includes one sync box + two pairs of Model X wired 3D glasses (or two pairs of Model X wireless 3D glasses). More wired glasses can be added by using standard stereo headphone splitters. Upgradeable to wireless by purchasing wireless glasses. The system will work on CRT(tube type) TV's and projectors. Glasses cord is 2M long but standard headphone extension cables can be used.