I am swimming with monofins for about 25 years - this is the best fin ever! Excellent gliding in the water, more speed with less power required. Good fitting at the feet, good connection of the power in the legs to the fin.
Just great!

Quick delivery from Estonia to Germany.
First impression: it's heavy (because of the rubber foot pockets and the 22 degree extension).
Easy to put on, enough space for the feet in the pockets.
In the water easy to handle from the beginning. It asks for stylish correct swimming but if you do, its driving you forward very quick without to much power to use. You really are gliding through the water. A very enjoyable feeling!
I am very happy with this fin!!!

Jetzt konnte ich die Flosse schon mehrfach Schwimmen und Tauchen. Beides macht richtig Spaß. Die Flosse ist super verarbeitet und macht einen richtig wertigen Eindruck, der sich in der Praxis bestätigt.

Die Leaderfins sind jetzt nicht das High End Produkte, aber Preis Leistung stimmt. Sie taugen sowohl für das Finswimming als auch für Apnoe, ich habe die Medium gewählt. Die Waterway Glide waren für das Finswimming besser, kosten aber auch mehr. Mehre Kontakte mit dem Support wegen Fußteilen und Größe erfolgten prompt und waren fachkundig. Die Lieferung vom Osten dauerte knapp 5 Tage, alles prima.

I'm living in Mayotte and I use every day the monofin, but it's my first time and I prefer again my leader fins carbon, more soft. I need more time to be easy with a heavy monofin.

Wonderful Perfect Monofin arrived in Brazil in 10 days super fast perfect finish better than I was expecting my first Monofin I'm in adaptation but already evolved a lot ... Wonderful bag everything perfect super competent and honest seller ... I will always buy from you thank you for attention .... Mad to debut in the championships of finswimming

Maravilhoso Monofin perfeito chegou no Brasil em 10 dias super rápido acabamento perfeito melhor do que eu estava esperando meu primeiro Monofin estou em adaptação mas já evolui muito ...Bag maravilhosa tudo perfeito vendedor super competente e honesto...vou comprar sempre de vcs obrigada pela atenção....Louca para estrear nos campeonatos de finswimming

I've already bought two of these fins and i'm really very happy with both of them:

I'm 5'9 and around 138 pounds. My feet are 26,5 cm (10,49 inch) long. The first one i ordered was 39-40 - stiffness Medium. I can only wear the included toe-socks in them (still a very tight fit).
I use it for pool-training (warmer water) / when i don't plan to wear it too long (max ~90min).

I got another one of the Leaderfins Hyper Carbon Monofin in the next bigger size (41-42) - also Medium. I need to wear at least 2mm full socks otherwise this one is too big (toe-socks only is not enough). I probably could even wear 4 or 5mm full-socks in it. It is more comfy and i plan to use it outdoors / in cooler water when wearing it for a longer period of time.

Be also aware that if the instep of your foot (the area after/behind the toes to the leg) is already starting very early and going up steep, you will also need a bigger size, as the entry of the fin is pretty tough and the rubber not very flexible. A friend of mine with nearly 1 inch shorter feet than me cannot even get in my smaller 39-40 fin as the entry is soon too small (he can just get the toes inside). For him the bigger 41-42 with toe-socks fits just fine (which would be too big for me - i need at least full socks). So my feet are somehow in between the two Leaderfin sizes for this monofin.

It has a weight of around 7 pounds - and therefore negative buoyancy. With my 1,5mm suit the weight of the fin is still so much that i tend to sink slowly already at water-level. That is no problem in the pool, but keep this in mind if going deep(er) and re-check the amount of additional weight you really need !

I'd also recommend getting the blade protection and the bag for this fin. Not sure about the hydro-wings - i will have the possibility to try one with these soon.

To my opinion it is overall a very good, comfortable and fast monofin (with the 22 degrees of angle), it is neither stressfull to your feet (compared to cheaper monofins and their footpocket-designs) nor does it fatigue your legs that much (as compared to bi-fins in my opinion) if you get/find the right size (that is the main-point - as the footpockets are not soft).

Quality product and descent shipping time.

I use the mono both in the sea and during pool sessions. It is well crafted and with the blade angle offers a good hydrodynamics, Foot pockets straight, but the use of the half-socks is recommended, in order not to stress toes and fore-foot