The shoe has been improved to better adapt to most different foot shapes. The Free Frog enjoys the exclusive characteristics of the Cressi underwater fins while maintaining the spirit of the legendary Frog. The blade originates directly from the upper part of the liner (liner subjected to the blade). to have a larger surface that increases the height of the foot and transmits all the effort generated by the kick without loss of energy It is produced with a variant of low modulus polypropylene which, combined with a particular structure, combines great flexibility, softness and resistance to a demanding use (also for rent in a diving center), unprecedented durability and aesthetics of the fins