Ranked Number One Fin
By The UK Dive Magazine

Tested against 20 other leading fins, the Tri-Ex came out on top. 
"the Imprex Tri-Ex from TUSA was by far the most comfortable fin tested."
Given a rating of 9.5 out of 10 the Tri-Ex is, "lightweight" and "highly manoeuvrable".
At a reasonable price the Imprex Tri-Ex is definately the way to go!

• Uses TUSA's unique Advanced Multi-Flex Blade, made from 3 different materials.
• Most of the foot pocket is covered by soft material, enhancing the fit and making it easier to put on or take off. eases squeezing pain.
• TUSA Patented easy-to-adjust strap features quick release buckles.

In 1993 TUSA introduced the SF-7700 (IMPREX fin) to the market. This fin achieves strong propulsionby combining two different materials to create an efficient water channeling action. Since it first went on sale, over 600,000 divers have used it worldwide. The IMPREX fin has been the undisputed leader in the plastic fin market. Now, ten years later, it is moving to the next development stage. The next generation IMPREX Tri-Ex fin utilizes three different materials. First is the side rib (hard material), efficiently converting the energy of a kick into propelling power. Second is the blade (medium-hard material), increasing the efficiency of the water channel. Third is the foot pocket (soft material), enhancing the fitting comfort of the boots. The designers expanded the blade angle theory that had produced a strong propulsion force with only a light kick in the SF-8 model. A fin testing robot was used to analyze the propulsion (speed) and the electrical load when kicking. Tests were also ran using real divers in a water circulating pool. These tests were repeated many times, the result being that the blade angle was set at 20 degrees, the most comfortable for the diver. A smooth shape was also created, with no level differences between the foot pocket and blade. This means that compared with conventional products, less initial load (energy) is required when first starting to kick. The excellent fit and non-wasteful transmission of energy ensures that body fatigue and air consumption is minimized.

Air Consumption Performance Test. Our in-house testing team performed some measurement tests on each of our fins to determine the air consumption for each one. Using an underwater speedometer to maintain a constant speed of 0.77m/s, we measured over and over how much tank air the swimmer consumed after swimming a fixed distance of 150 m. Measuring energy efficiency allows us to develop fins which deliver maximum speed with the minimum fatigue.

Fin Testing Robot. This test involves scientific testing of energy consumption rates and speed performance, and then analyzing the resulting data. TUSA's battery-driven fin robot kicks at a very precise pitch while a telemetry system using a computer by the pool wirelessly measures the electrical resistance load (i.e. the energy consumption rate). For instance, we can measure how long it takes the robot to swim across a 20m pool and what the electrical resistance load was during that time in order to evaluate fin performance in a manner that's much more scientific than possible with human testers.

Flow Pool Test. TUSA has had the honor of doing joint research on fin energy consumption with the Nomura Swimming Research Lab at Tsukuba University in Japan. One test included having four adult male swimmers use our fins in a flow pool while we measured their oxygen uptake and heart rates. We were also able to scientifically evaluate the differences among different leg muscles and fin kicking, as well as measure the pressure applied to the front and back of the fins using air-pack contact pressure meters. The Nomura Research Lab analyzed the data we got from these tests and we applied the results to our product development process.

Global Monitoring. However, we realize that testing under real conditions is very important. That's why we send out prototype models to diving shops around the world during the development process, in order to have real instructors and guide divers test them in normal circumstances. Even after a concept makes it out of the prototype stage and goes on sale, we have monitoring groups which are made up of regular divers who use the products and let us know their opinions, which we feed back into the development process.