In this picture of Page with the final line up of the Yardbirds you can see his Tonebender Professional MII. See also this shot with Zep: http://www.bigmuffpage.com/images/Tonebender%20Images/Screaming%20Lord%20Such_May%201969_TB.jpg and this informative article on the history of the Bender family of fuzzes with a healthy dose of 'ol Pagey interspersed: http://www.bigmuffpage.com/The_Tonebender_Timeline_4.htmlmore
"The various iterations of the Tone Bender have had many circuit configurations, but it’s best known as a three-transistor germanium design, typified by the Professional MKII. This is the pedal associated with Jimmy Page during the early days of Led Zeppelin, and was a key component of Eric Clapton’s “Woman Tone” on the Disraeli Gears album by Cream." According to writer Tom Hughes, author of *Analog Man’s Guide To Vintage Effects*more
I love the Sola MK2 professional. It does a great Page thing, cleans up well with your volume control without changing its frequency response AND has the best and smoothest sustain for leads of any 3 transistor, 2 control fuzz pedal I know of. I sold mine for a mint. I miss it a lot. The treble can get out of control though, so if you don't like a toppy sound or have a crazy bright amp then get a MK3 or Burns Buzzaround (or clones thereof).
Most vintage MK2 Pros sound uniformly excellent though there is a lil variation in what sort of excellence they give you. These pedals are valuable and collectable but were made in massive quantities so you can find them. If you want to spend less, there are lots of great clones out there. I was quite impressed with the MJM Brit Bender, though DAM makes the most accurate recreation if you wanna spend a lot.