Diving fins
EXPRESS Sea Quest

The blade is not directly attached to the front of the foot pocket. The fulcrum point is at the patented mid-foot location, known as the "mid-foot flex joint". This takes the strain off of the toes and ankle and allows the entire foot to be used. This results in incredible comfort.

To bridge the gap between blade and foot pocket an "armadillo" membrane is used. The "armadillo" is a patented, elongating membrane made out of super-elastic rubber. It serves two functions:

Accumulates elastic energy during each kick and gives it back at the end of the kick

Make a complete connection between foot pocket and blade, eliminating hydrodynamic gap that water can move through