Yeah Eugene, they have the three slots in them. I never thought of them as stiff though, but now that you mention it...
I looked up those Zoomers. Bizzare, yet interesting: http://www.montecitosports.com/product_pages/Swim/Zoomers.html?OVRAW=zoomer%20sw im%20fins&OVKEY=fins%20zoomers&OVMTC=advanced
I guess if I relate to fins like a car's transmission, no fins would be 1st gear, Zoomers would be second gear, my fins would be fourth, and the long freediver fins would be overdrive, sorta. I was swimming the river last year and noticed I had a hard time getting my heart beat up without fatiguing my legs. Zoomers look like they're just what I need. Gotta get me some.
Also on the link above, they show what they call Seal Goggles. I like! I bought one for riding my waverunner, so I don't lose my contacts when I wipe out. It works. Took a spill and flopped all over the water at about sixty mph. Hurt like hell and got some great laughs, but the mask stayed on. Doesn't have a nose piece. Rather disconcerting the first time I snorkeled with it.
Site above also has a $130 snorkel. I'm trying to figure out the usefulness of a purge valve in a snorkel. Guess there's a sucker born every minute.
They have a waterproof electronic metronome too, which would be pretty neat for your drills.
But an underwater radio???