The SF-6 Imprex Tri-Ex fin features TUSA’s Advanced Multi-Flex Blade, made from 3 different materials which reduces diver fatigue and air consumption for fast and powerful propulsion from a traditional blade fin.

In 1993 TUSA introduced the SF-7700 (IMPREX) to the market. This fin achieves strong propulsion by combining two different materials to create efficient water channeling action. The IMPREX fin has been the undisputed leader in the plastic fin market. 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 and transferring power to the ribs and blade. The designers expanded the blade angle theory of the SF-8 X-Pert Zoom that had produced a strong propulsion force with only a light kick. A fin testing robot was used to analyze the propulsion (speed) and the electrical load when kicking. 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.

Angled Blade Design (A.B.D.)
When using the standard traditional blade fin, with the leg completely extended, there remains an angle of 27 degrees between the heel and the foot and the calf of the leg, causing a 10% loss of propulsion. Because the fin is angled below the body, during the kick phase, the body is pushed forward and down, instead of straight ahead. With the SF-15 fin, that 27 degree angle has been designed into the fin. This means that 100% of the energy expended during the kick phase is directed toward the propulsion of the diver. TUSA developed a robot that can replicate the kick-cycle and movement of a human's leg. The robot is able to mimic the motion of a human exactly and relay accurate data. TUSA has been able to analyze the performance of the fins under several conditions. The robot is able to simulate swimming through the water using kick variations, such as a large scissor kick with a slow repetition and vice versa. Using the latest technology, this robot measures the energy expended during the kick and the propulsive force that is created using that energy. To achieve maximum performance from this fin, use a small bent-knee kick with a light rhythm. This creates less strain on the leg muscles compared with traditional fins, reducing the diver's fatigue and subsequent air consumption.

H.B.S. (Hybrid Blade System)
The patented Hybrid Blade System offers unparalleled propulsion, efficiency and power transfer in a multi-compound design. The H.B.S. is composed of incredibly stiff urethane side rails and an ultra-responsive membrane blade giving unlimited kicking potential.

EZ Strap and Buckle System
TUSA's EZ strap and Buckle System allows fins to be quickly and easily adjusted with minimal effort. Adjustment can be made while the fins are worn, allowing for a precise fit and ease of removal when necessary.