Size: 12-inch (same size as standard LP album) Blank laserdisc manufactured for use in industrial analog laser videodisc recorders, in use in the 1980s through mid-1990s, which are very rare. Laser Videodisc recorders were never available to the general public, so the price of the machines was always extreme. This is like a giant 12-inch CD-R, except it is an "LD-R". This now-obsolete technology preceded DVD technology. Although video was recorded onto these discs with a laser, similar to the way a CD or DVD is recorded, the video signal was actually analog rather than digital. The audio soundtrack was stereo analog, but later on a CD-quality digital stereo signal could also be recorded. (Although I'm not sure what the industrial recorders were capable of.) For more information about LD technology, see: http://en.wikipedia.org/wiki/Laserdisc This analog videodisc technology could only store 30 minutes of video on one 12-inch side, in the "CAV" format. CAV means the disc spins at a constant "velocity" (speed)... in this case, it is 1800 RPM. Laserdisc also had another mode called "CLV", Constant Linear Velocity, which spins the same way as a CD or DVD, faster in the inner part of the disc (1800 RPM) and slower toward the outer rim (600 RPM), resulting in a recording time of 1 hour per side. Since this is still sealed, I am not sure if this is is single-sided disc or double-sided, but my guess is it is only single-sided. I have two that are open and have been used, which are single-sided. One side is plain white plastic, and the other is polycarbonate (like a large 12" CD) - these are actually 2 discs glued together. The disc image is of one of the used discs, to give you an idea of what it looks like: