This project was the result of the exceptional experience of Martin Stepanek, one of the greatest competitive freedivers of all times, combined with the 30 years of experience of the C4 carbon fiber fin Co. of Marco Bonfanti.

Stepanek’s signature fin features TR50-Hypertech Big Square, an even more responsive carbon fiber material compared to the already highly proven T700 adopted previously by C4. 

After a year of long testing, Martin carefully developed a fin with C4 that fit his needs and catered to the most important needs of freedivers and spearfishers from his experience in American waters.