Profile has completely changed their product line in the last year with an intense focus on fit range and adjustability. In their alloy product offerings the sonic bracket and ergo armrests hugely increase the range of adjustment. In carbon the supersonic bracket replaces the sonic but it is identical to the former J5. There is a wider range of extensions from the 35 (a for alloy or c for carbon), 45/25, 43, 50, and the T5 still exists with the addition of the sonic bracket in Sonic ergo T5. Overall the extensions are longer with a more complex design adding lateral bends whereas the former T series did not have any lateral bends. These shapes allow for a closer or wider hand position without having to move the armrests as narrow or wide. This can make a big difference in comfort for triathletes that like a close hand position, but don't want the tension in their neck and shoulders.
The latest design for their ITU draft legal bar is the Sonic Ergo 45ar. With the sonic bracket / ergo armrest a much, much wider range of adjustment is possible, and it is easier to shorten to meet ITU regulations.
The Flip Ergo 50a replaces the venerable Airstryke bar which has been around for ever. It too gets the sonic/ergo treatment but adds the 50a extensions instead of the bridged older design. This again greatly improves fit range and adjustment.
The Sonic Ergo 43a borrows on the design of the former T3 extensions which was my favorite for riders wanting a versatile cockpit. The basic shape is very similar to the T3 with an added lateral shift of 7.5mm. They tout wrist relief for this bar but I like it for the ability to move your hands under the bar and "choke up" for more leverage when passing, sprinting, or time trialing, but a neutral hand position can be resumed.
Finally the Hypersonic 50a rounds out their low mount offering. For those that want the most aggressive, aerodynamic, position possible this bar puts the armrest as close as possible to the base or pursuit bar.