Regular price SFr. 990.00
Unit price per
Double K Delfit Monofin
The Double K Delfit Monofin is a high-performance carbon monofin built for freedivers who want powerful propulsion, precise blade response and a secure foot pocket connection.
The Delfit system combines a high-elasticity carbon blade, autoclave-molded construction and Double K’s dedicated Delfit foot pockets. The result is a responsive monofin for dynamic apnea, CWT, depth training and serious monofin technique work.
Available in White, Red and Black, with blade stiffness options S, MS and M.
Why choose the Double K Delfit Monofin?
A monofin is only as good as the connection between the diver, the foot pockets and the blade. The Delfit is designed around that connection: a secure foot pocket system, a high-elasticity carbon blade and a wing-inspired structure that helps convert dolphin-kick movement into forward propulsion.
Double K positions the Delfit around three core ideas: lightweight construction, positive buoyancy and comfort. The foot pocket system is designed to sit closely around the foot, especially when used with silicone socks, improving comfort and force transfer while reducing empty space inside the pocket.
Main benefits
- High-elasticity carbon blade for strong and responsive propulsion
- Autoclave-molded carbon construction for consistent blade performance
- Delfit foot pocket system for secure fit and efficient force transfer
- Wing-inspired structure designed to improve directional stability and speed
- Positive-buoyancy design focus for balanced handling in the water
- Three stiffness options: S, MS and M
- Three colour setups: White, Red and Black
- Suitable for dynamic apnea, CWT, depth training and monofin technique
Delfit foot pocket system
The Delfit foot pocket is one of the strongest arguments for this monofin. In a monofin, the foot pocket is not just a comfort part. It controls how directly your kick force reaches the blade.
If the foot pocket is too loose, power is lost before the blade reacts. If it is too tight, the diver loses relaxation, comfort and control. The Delfit system is designed to create a close, stable fit while keeping the setup comfortable enough for repeated training.
Double K specifically refers to the use of silicone soft socks. According to the manufacturer’s sizing graphic, wearing Double K silicone socks makes the fit approximately 1 mm tighter, helping remove empty space, improve force transfer and reduce foot discomfort.
Blade and propulsion concept
The Delfit blade uses a high-elasticity carbon construction and a wing-style outline to help convert the force of the kick into rebound and forward movement. The goal is simple: more propulsion from a smaller, cleaner kick.
Double K describes the Delfit concept around stronger propulsion, improved straight-line tracking, increased speed and reduced physical effort during finning. This should be understood as the design intention: efficient movement, cleaner direction and less wasted energy.
Blade stiffness guide
| Stiffness | Best use | Kaluna recommendation |
|---|---|---|
| S | Dynamic apnea / pool training | Choose S if you want a softer blade, easier rhythm and repeated pool sets. |
| MS | Allround freediving | Choose MS if you want the safest default option for most freedivers. |
| M | Depth / stronger kick | Choose M if you are a stronger diver or prefer more resistance and blade response. |
If you are unsure, MS is usually the most sensible allround choice. S is more dynamic-focused. M is more depth- and power-focused.
Colour options
The Double K Delfit Monofin is available in three colour setups:
- White - clean, bright and highly visible in pool photos and videos
- Red - strong contrast and the most aggressive visual setup
- Black - minimal, technical and understated
The blade remains carbon-dark. The selected colour mainly affects the foot pockets, rails and trim details.
Foot pocket size guide
For the best fit, choose the Delfit foot pocket size based on measured foot length in millimetres, forefoot width and whether you use silicone socks. EU shoe sizes are included as a practical reference, but foot length is more reliable than shoe size alone.
Double K Silicone Soft Socks make the fit approximately 1 mm tighter. This can help remove empty space, improve power transfer and reduce foot discomfort.
Important: Double K’s size chart includes #1 for very small standard forefeet, but the public Delfit monofin product selector currently lists foot pocket sizes #2–#8. If your table result is #1, contact us before ordering.
For a high-end monofin, sizing should not be guessed. Send us your measured foot length, forefoot width and sock choice if you are unsure.
Text version of the Delfit foot pocket size guide
Barefoot / without silicone socks
| Foot length / EU approx. | Wide forefoot | Standard forefoot | Narrow forefoot |
|---|---|---|---|
| 210 mm / EU 32–33 | #2 | #1 | - |
| 220 mm / EU 34–35 | #3 | #2 | - |
| 230 mm / EU 36–37 | #4 | #3 | #2 |
| 240 mm / EU 37–38 | #5 | #4 | #3 |
| 250 mm / EU 38–39 | #6 | #5 | #4 |
| 260 mm / EU 40–41 | #7 | #6 | #5 |
| 270 mm / EU 42–43 | #8 | #7 | #6 |
| 280 mm / EU 44–45 | - | #8 | #7 |
With Double K Silicone Soft Socks
| Foot length / EU approx. | Wide forefoot | Standard forefoot | Narrow forefoot |
|---|---|---|---|
| 210 mm / EU 32–33 | #3 | #2 | - |
| 220 mm / EU 34–35 | #4 | #3 | #2 |
| 230 mm / EU 36–37 | #5 | #4 | #3 |
| 240 mm / EU 37–38 | #6 | #5 | #4 |
| 250 mm / EU 38–39 | #7 | #6 | #5 |
| 260 mm / EU 40–41 | #8 | #7 | #6 |
| 270 mm / EU 42–43 | - | #8 | #7 |
| 280 mm / EU 44–45 | - | - | #8 |
Technical details
| Brand | Double K |
|---|---|
| Model | Delfit Monofin |
| Product type | Carbon freediving monofin |
| Blade material | High-elasticity carbon |
| Carbon weave | 3K Twill |
| Carbon layers | 15 layers |
| Manufacturing method | Autoclave molding |
| Foot pocket material | Rubber + EVA |
| Blade stiffness | S, MS, M |
| Colours | White, Red, Black |
| Foot pocket sizes | #2, #3, #4, #5, #6, #7, #8 |
| Approx. dimensions | 73 cm length x 70 cm width |
| Manufacturer weight note | 900 g based on one side, size #2, according to the manufacturer graphic |
| Recommended use | Dynamic apnea, CWT, depth training, monofin technique |
| Production | Custom made / lead time to be confirmed before ordering |
Is this the right monofin for you?
Choose the Double K Delfit Monofin if you want a serious carbon monofin for structured freediving training. It is best suited to divers who want strong propulsion, clean blade response and a close foot pocket connection.
It makes sense for:
- Dynamic apnea training
- CWT and depth-focused freediving
- Monofin technique development
- Freedivers moving from basic equipment into performance gear
- Athletes who want to choose blade stiffness instead of buying a generic setup
- Divers who care about foot pocket fit and power transfer
Kaluna Freediving Opinion
The Delfit Monofin is interesting because Double K does not treat the foot pocket as an afterthought. For monofin, that matters. A blade can be excellent, but if the foot pocket connection is weak, power transfer becomes sloppy.
The strongest setup for most freedivers will usually be MS stiffness, unless the use case is clearly dynamic-specific or depth-specific. S makes sense for pool rhythm and repeated dynamic work. M makes sense for stronger divers who want more resistance and depth performance.
Colour is personal. The important decisions are foot pocket size, socks and blade stiffness. If those are right, the monofin can work as a long-term performance tool. If those are wrong, even a good carbon blade will feel wrong in the water.
FAQ
Which stiffness should I choose?
Choose S for dynamic apnea and softer pool work, MS for the most versatile allround setup, and M for stronger divers or depth-focused training. If you are unsure, MS is usually the safest starting point.
Which colour should I choose?
Choose White for a clean and visible look, Red for the strongest visual contrast, or Black for a more minimal technical setup. Colour is personal; stiffness and foot pocket size matter more.
How should the foot pocket fit?
The fit should be close and stable without creating painful pressure points. If the foot moves inside the pocket before the blade reacts, power transfer becomes less efficient.
Should I use silicone socks?
Silicone socks can make the fit tighter, reduce empty space and improve grip inside the foot pocket. Double K’s own sizing graphic states that silicone socks make the fit approximately 1 mm tighter.
How long does production take?
Double K lists the blade as custom made with an approximate 2-month production time. Final lead time should be confirmed before ordering, especially for specific colour, size and stiffness combinations.
Can the Delfit Monofin be repaired?
According to the manufacturer Q&A graphic, the monofin is produced as an integrated system, so foot pocket or blade repair is not normally possible. Water rail replacement may be possible. Contact us before assuming that a repair can be done.
Can I test the fit before ordering?
Fit is critical for this product. If you are unsure about size, contact us before ordering with your measured foot length, foot width and sock choice.
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