The one with the 3 coil springs is the B-73. I have one that's 42 years old. Gotta be careful or I could fall asleep on that thing! Until I get a Honey B-67 (2 springs)for my Trek 520, it is The One. Got some nice comments today on it at the Internat'l Bike Expo in Seattle. Rode it down there and back, 62 miles rt. Over 300 miles on it in the past 8 days. Plenty skinny for riding the drops, which I usually don't do, but wide and comfy for the more upright position.
There's something else about sprung saddles that a mechanic at Expo brought up: for heavier riders, especially aggressive ones like me, he believes a sprung saddle saves wear and tear on the frame???
Comments on that? Or, should it be a thread?