Launched on the market in occasion of the Eudi Show 2015, the C4 HT Mustang and HT 83 fins are a real revolution.

We have wanted to understand and go deep into the subject with the “father” of the new pearls by C4, Marco Bonfanti, and ask how and how much the new Mustang and 83 HT offer advantages if compared to the very efficient and well known 729 Mustang and 82 made of T700.

AP When did you think about the HT and when have studies began?

MB It does not really work in such way for me. Studies on the fins and materials are always ongoing. When I have gained new and significant technical knowledge and commercial conditions are right, without which companies cannot live, I start the production of a new product. For the HT this has began more or less one and a half years ago.

AP Which difficulties did you find in manufacturing the new fins with the TR50 Big Square carbon fiber compared to the T700?

MB All of our production is “100% hand made”, so, after I have technically designed a product, it is necessary to train personell for production. This is the main obstacle, as a change like this one, both of texture and resin, now in prepreg, for the craftmen is a revolution in their work. Also, the technical definition of the product has been challenging, since I wanted fins that were significantly superior to the 729 Mustang. Time and many tests, this is the only valid approach.

AP How much does the material gain in reactivity if compared to the T700?

MB Considering the fiber, T700 stands for the material with no resin, carachteristics are the same. The difference is made by the final result with resin, meaning the composite material: the structure is more compact, the composite is optimized with less crossings and ondulations of the fiber. Also, the quantity of resin is reduced, and all of this improves the elastic response. You will not notice this bending the blades outside the water, but you will absolutely feel the difference in the sea.

AP Resistance to breakage remains the same of the T700?

MB Resistance to traction is identical, meaning still 40% more than standard solutions, while the elastic module is slightly greater.

AP In addition to a difference in the width of the unidirectional bands of carbon fiber, equal to 25 mm compared to the 14 mm of the T700, are there any particular differences between the two textures?

MB Yes, the thickness of the texture itself changes, but this data is not significant for the fins behaviour, while the final composite makes the difference.

AP Who are the HT fins for, if compared to the Performance line, and which are the differences that will be felt during use?

MB The HT-line fins have superior performance to any other fins we have manufactured in the past. Faster with need of less effort, in the water the difference can be well felt. I have myself been surprized by the speed of these fins. I knew they were superior, but did not expect such a difference. We suggest such product to those divers that appreciate advanced technique and look for faster fins.

AP In which conditions will the advantages be felt in particular? Start, accelleration, speed, other?

MB The start/acceleration will be similar to the T700, this is due to the fact that such aspect depends mainly on the rigidity of the blade and the height of the water rails. Speed instead changes significantly. We will find ourselves moving on long distances without any particular effort.

AP The dimensions of the Mustang HT and 83 HT vary respect to the same models of the Performance line?

MB The HT- Mustang are slightly longer (+ 15 mm), while the 83 have the same identical dimensions of the 82.

AP Doesn’t the Hi-Gloss superficial coating risk to have negative effects during spearfishing because of the increased reflects of sunlight? Was it not better to offer the customer two different solutions, gloss or matt?

MB Being immersed in the water makes almost all smooth surfaces also polished. Think of those fish that are perfectly mimetic, but anyway reflect light. We already have in C4 sufficient models of strong carachterization in our fin line, and we must not use aestethic solutions to differ one from the other.

AP Which will be the next HT models?

MB HT-RED Falcon and HT-BLUE Flap…evidently.

AP Which are the prices of the Mustang and 83 HT?

MB On our website,, it is possible to request price list. As always, the final price will be defined by our stores around the world.

AP Which have been the comments of your champions when they have tried the HT? Can you simply give me the words these athletes have used, also comparing the new fins with the T700?

MB I will do more, I have sent the question directly to the athletes, here are their opinions.

Renzo Mazzarri

“I believe I have been the first professional diver to use carbon fiber fins. Already from the first prototype by Marco Bonfanti, the difference compared to traditional fins, was as deep as the ocean. For such reason I have dedicated to Marco my biggest victory. I wrote at that time that, without Marco’s fins, I would not have won the World Championship in Maiorca in 1992, disputed at extremely deep depths.

(at such World Championship in Maiorca 70 athletes participated. Only 4 of them had carbon fiber fins, all by C4, as at that time no other existed, The athletes were the three of the Italian National team plus Salvatori. They were strong, and achieved 1°, 2°, 4° and 5° position.)

“Since then, the passion, but mainly the research by Marco, have led to many evolutions, with always small but significative improvements of the fin. I have tried the last product, the HT 83 only in the swimming pool, while I have tried in the swimming pool and I currently use the Mustang HT in the sea, where the improvement with the T700 is evident. I have always used rigid baldes (the 40), but my identity card has constricted me to move to the softer 25. With the HT I manage to obtain the same speed, especially in the ascent phase after a deep dive, with much less effort, giving me great advantage for the total apnoea. Since though, as Marco says, if I do not have to put effort I am not happy, and until my legs will let me do so, thanks to the advantage given by the HT, I have been able to go back to a slightly stiffer blade, the 30, meaning I am able now, with the same dive time, to reach greater depths.

Riccardo Molteni

“To illustrate the new and astonishing technical details of the new fins by Marco (reduced inertia, different elastic return, different hysteresis cycles during finning, ect.), Marco is the right person. I simply would like to make some observations, as lucky utilizer.

I have been using for a long time the Mustang 729 with stiffness of 40, extraordinary fins, and since last May I use the Mustang HT and have moved to stiffness 30. I must say that such an improvement was really unpredictable, on fins that, after all, could be considered a simple renewal of the previous: but that’s not the case! These new fins are really something different. The main feel is the reduced muscular effort needed for the same performance, especially at the start and in deep dives, with positive effects on the duration of the apnoea (less oxygen consumption) and the global lucidity of the fishing action. To give the best idea of what just said, I want to point out that the use of such fins (and I repeat with softer blades, 30, than the ones I previously used, 40), is giving me the possibility to use 0,5 kg more of weight in my belt (+ 10-15%) in Summer period deep fishing sessions, with the effect of reaching a negative set-up some meters before usual, and lengthening the tajectory of the glide with the legs still and relaxed muscles, but, at the same time, feeling no difference in the start from the bottom. All this translates in better performance at the bottom, without having to compromize the efficiency of finning, which can always be very light, effective and not particularly energy consuming during ascent.

AP For those divers used to the T700, is there an equivalent stiffness value of the blades of the HT compared to the Performance?

MB The values are the same, 25, 30 and 40. We can say though that, because of the reduction of the effort requested, some divers have preferred the higher level stiffness. This means they will fin with a base effort that will not change moving from the T700 of lower stiffness to the HT of higher stiffness. Some divers will then apply the same strength to move faster, while others, such as me, will reduce effort obtaining still the same speed.

AP Let’s now talk about the new Stepanek line. Which carachteristics do these fins have compared to the other C4 solutions? Are they already on the market? At what price?

MB These fins are finally ready. They will also be made with the HT fiber. Martin has deliberated a fin following his exceptional experience, and C4 has simply followed his indications. Measures, angle, shape of the water rails are different compared to the other C4 fins. For prices please refer to C4 website.

Click Like on Facebook page to be updated with new interviews and deep product presentations!