If you want build that power into your legs, go for the hard ones. They are excellent! You wont regret the buy. Just have to scrub them in for that leg position to settle, can be tight on the foot at the beginning.

I was looking for a pair of "rubber" fins with some "muscle" similar to the classic UDT Duck Feet which I am a big fan of. These however are NOT made of real Rubber! The material is consequently not so soft and forgiving on the foot. The sizing runs small and as a 44-45 foot I found the fit too tight but otherwise snug. The design and flex seems excellent however and if they were more comfortable would have gone with them! I have given them away to my Son in law to give a try as he has smaller feet to me. The Balco "Sprints" are way more comfy (cos they're lovely soft springy rubber) The hunt for the perfect blend of power and comfort continues! I cant be doing with all these Plastic fins! Oh! one more thing! The photo is a little confusing! You are looking at the bottom of the fin. the hole is in the top not the bottom. It is a very ergonomically advanced design I think.