The idea is to reduce the bulk of the rescue personnel by exchanging the classical swimming fins with foldable, compact fins.
The description of the foldable fin is available at http://www.exofin.pl. Pictures of the product are attached.
The main advantages of these fins are weight and compactness when folded. When unfolded fins have surface significantly larger than commonly used rescue, compact fins which translate into better efficiency when swimming. The producer claims that the fins can be custom adjusted e.g. shorten to fit preferences of the individual SAR operators.