That's an illegal bootleg, like all other offers of the "complete" series on DVD, culled from off-air recordings or old VHS and Laser Disc releases with inferior quality to the official releases (devoid as they are of worthy extras). Save your money and stick to the legit releases on DVD.
The only place I know of that you can get the complete collection of the 70's episodes is Japan. They haven't released the 90's eps though. There's someone on ebay selling the japanese boxset.