Cressi’s most technically advanced fin, the Reaction uses a completely new polypropylene blade material that is more reactive, flexible and trim than previous designs.
It kicks easily yet powerfully and is suitable for divers of every experience level.
The longer blade efficiently transfers energy from the computer-designed foot pocket, and like other Cressi fins, the blade extends from the top of the foot pocket to maximize its effective surface area for more thrust.
Other innovations include new locking strap buckles and anti-slip material for better traction out of the water.
EBS strap
https://cressi.com/Catalogue/CressiTech.asp?id=1289&sez=1
Cressi has developed this special strap to meet the needs of the most demanding divers, who need a comfortable fastening for their foot but one that is still practical and manageable.
Its special amply sized slot makes it very easy to put on, even when wearing thick gloves or three-fingered gloves for winter water.
The wrapping section is highly flexible, making adjustments unnecessary, and as a result it’s much easier to get all your equipment right in the first few meters of your descent and the fin stays in place against your foot despite the increase in hydrostatic pressure.