C4 L-1090 Freediving Blade – Stiffness 30 Medium

C4 L-1090 Freediving Blade in HT15 Carbon – Stiffness 30 Medium

The C4 L-1090 Freediving Blade stiffness 30 Medium is a high-performance carbon freediving fin blade, designed and manufactured by C4 Carbon for competitive and sport freediving. Available in stiffness ratings 20 (Extra Soft), 25 (Soft) and 30 (Medium), this Medium version is ideal for freedivers with a solid kicking technique who seek an optimal balance between reactivity and propulsion. Price for a single blade.

Progressive Lamination with 4 Japanese Carbon Types

C4 L-1090 blades are manufactured using a new progressive lamination of carbon layers, achieved by combining 4 different types of Japanese carbon, each selected specifically for its role in the composite structure. This technology simultaneously optimises the reactivity and mechanical strength of the blade.

The laminate structure consists of:

• HT15 carbon as the outer layer – an exclusive C4 technology providing superior lightness and surface rigidity
• 7 intermediate layers of high-resistance fabric – to absorb cyclic stress during the fin kick
• Calibrated unidirectional layers – precisely distributed to shape a progressive flex profile

The combination of these elements delivers unique reactivity and outstanding fatigue resistance, even after intensive use in saltwater.

Overmoulded Variable-Geometry Water Rails

The water rails on C4 Series 200 blades are not glued but overmoulded at high pressure and temperature directly onto the composite, through a patented process that allows the plastic material to fuse structurally with the blade. This technique, developed in-house by C4 engineers, eliminates the delamination risk typical of manually bonded water rails.

The polymer used for the water rails retains its elasticity over time up to four times longer than standard NBR, ensuring consistent performance over the long term.

The variable geometry of the water rails is designed to optimise hydrodynamics along the entire length of the blade:

• Near the foot pocket, the profile is low to avoid overloading the blade with water
• Towards the tip, the water rails progressively rise to channel water flow and prevent pressure loss and unwanted lateral drift

Finish and Design

The surface finish is exposed carbon (carbon look) with a single-colour white decoration. The water rails are asymmetric two-tone in black and white, for a technical and distinctive aesthetic.

Technical Specifications