The Speedo Pulling Ankle Lock definately prevents the legs from kicking and puts the focus on pulling yourself through the water.  But after using the ankle lock for about a week, the stitching is starting to pull apart.  I'm not sure if it is the force of the flip turn push off that is causing this or just using it.  A very good product to use if it can stay together.

Helpful in keeping feet together.  Generally use a pull buoy in conjunction with ankle lock.

Stitching started to come out within the first couple uses. Needed to be restitched by the third use. Industrial thread seems to do the trick.

I'm a triathlete so i must maximize body position.  Thought this would help.  However, I have to maintain a quick  water speed to stay afloat.  With no leg kick, my legs drag and slightlly begin to sink after about 100m.  I'm sure with increased use, the tool will improve my skill set dramatically.

I use these every day at my high school swim practice and they are great, I stoped using a pull bouey with them and it is a much better work out

i tested this product out when i bought it, because i was curious as to how it felt. i have one gripe about them... they are too close together for my legs. i have to try and press my ankles closer together than they naturally would be, which feels very wierd and a little uncomfortable. as a result, the straps dont quite fasten completely around my ankles.
i think an improvement would be to make a connecting piece about 1-2 inches in length, that is sewn to the ankle straps. my ankles do not touch each other (skin on skin) so neither should this.