Whichever type of bar you choose for your bike, it is important that the arm rests can be adjusted easily to provide optimum comfort for your arms whilst cycling, especially on longer races. It can take some time to get used to having aerobars on your bike, so prior to competing in a race, do ensure that you spend time practicing using these bars.
In choosing aerobars, cost will almost always be an important consideration, as this can vary significantly. Bars can cost anywhere from £40 up to £700 or more, but the higher the price tag doesn't necessarily mean the better the performance. A great deal depends on how you use the bars and your individual riding style. No matter how much you pay for your bars, they should always be comfortable. If they are too high up, the drag can increase, but if they are too low down and your knees are hitting your chest when you cycle, this could impact upon your breathing. In general terms, the most expensive type of aerobars are full carbon monocoque designs.
Some tri bars are specifically designed for either male or female cyclists, but it's worth bearing in mind that in the majority of cases, a good set of aerobars will be adjustable, and should be usable for both genders.