I used to have a Guinness Book of World Records with them in it. I think it was the 1976 edition; I got it for my birthday.
That's the work of Garrett Blake, at 2x2 Cycles, in Durham, NC. He can mount them to almost any kind of motorcycle. I'll have one on my new Tracer 9 GT soon. A friend of mine has an earlier, horizontal mount for his Harley and uses it to commute to our group rides routinely.
Hard to believe that just being obese twin brother motorcycle enthusiasts could make you famous in the 70s.