TFX stands for Titanium Front Exhaust. The TXF uses the same all Titanium first stage that is on the T3 and T25 regulators, but comes with the new 4X Yoke screw that tightens down with only one full rotation of the Yoke knob. The FTX is also available in a DIN option.
The TFX second stage has a front facing diaphragm and exhaust, which helps reduce breathing/cracking effort. Most regulators have anywhere from a 1.2-1.6 cracking effort and have increased breathing effort when in certain positions, such as looking up or on your back. Second stages with the classic design also have a tendency to breathe wet, due to water coming in under the exhaust tee when the diver exhales. The TFX on other hand has less than half the breathing/cracking effort and offers effortless breathing. Regardless of your position and due to the location and positioning of the exhaust diaphragm, it also eliminates water from being able to enter during exhalation, making the TFX the the most "natural breathing" regulator on the market. The TFX is also lightweight and has superior corrosion resistant due to all metal components being made from Titanium.