Okay, I bought a monofin and I am really stoked. The review will be in two catagories, what I like and what I don't.
What I liked: It's a total rage. I put it on and launched. The speed you get from a monofin is exhillerating. So much so that I stopped kicking two lines from the wall so I wouldn't get injured. There are many different models of the monofin. I purchased the "monofin trainer". It is billed as a fin that developes core strength and enhance your ability to do the butterfly kick. Personally I thought the latter was bologna but the claim seems valid after using. My friends who tried it on and/or had a weak fly; (Yes, I too have a weak 'fly), instantly took to it and started undulating immediately. My butterfly kick has greatly improved in just two workouts. It's great therapy and practice for those that want to master strong dolphin kicks after a flip turn.
The monofin is both hard and great for your feet and ankles. If your ankles and feet are tight like mine, your ankles get hammered; (i.e. they get tired and prone to cramping if you are fatigued after a workout.) I found I could only wear them 15 minutes at a time.
When workout was over we went into the deep end and let loose. It was like being a dolphin and all you can do is just smile while swimming.
What I don't liked: I have really high arches and the X-Large fins hurt my feet a bit. I wear a size 10-11 shoe size and the X-Large is suppose to accomodate up to size 12; (There is an xx-Large size), I probably should have gone a little larger. If you can try a pair on first, do it.
The monofin is not entirely made of rubber. The blade itself is made of what I believe to be plexiglass, hence, it is really sharp on the edges and can cut you if you are not careful handling them or another person if they accidently get hit by the business end of the blade. Wear this blade in your own lane or on your own time since it's a potentially dangerous to other swimmers.
