Troy Lee Designs A3 Mips Helmet Uno Red: A1 has been celebrated as being the most comfortable helmet ever made. The A2 is known as being one of the most ventilated and safest helmets on the market. Using years of intel from these helmets brings to market the most advanced half shell trail helmet ever produced; the A3. Safety, style and superior comfort will have an all new benchmark. So comfortable you won’t ever want to take it off.