I hope this review helps you in your shopping. I always depend on them before I buy. I bought these to use in a float tube for fishing. They were larger than I expected, but I decided to give them a try. I am 65 and my little bird legs balked at them at first. But they turned out to be great. I can wear them over stocking foot waders or small tennis shoes. And these things really propel. I had my wife take me a mile up a river and let me out. I had to kick my way for that mile and then another half mile against a quartering wind to get back to our campsite. I have a bad knee and was truly worried about how I would feel the next day. I can't really describe the excitement I felt that next morning. My calves were a little sore from not getting much exercise. And I could feel tightness in my thighs. And best of all, I could feel some tightness in my abs. You may not like the sound of all that, but it was heaven to me. I am a doctor and don't get much exercise. I can't jog because of my knee. These did not stress my knee at all. I have found a way to exercise calves, thighs and abs while having the fun of paddling around the lake and fishing. A great product.