This one is an exception. The instructions were terrible, construction was a nightmare and things didn't fit together well. Still, it did actually work. The video was made a while ago, with the giveaway having long found a new home.
The video is presented here because you can still find these antenna tuners on eBay. And you might find, what was easily my worst review of any piece of equipment I've had, entertaining!
PS: For some better antenna couplers that you can build yourself, check out Hand-carried QRP antennas. It's available in either ebook or paperback form. Couplers are just the start - there's also ideas and designs for numerous portable and pedestrian mobile QRP antennas.