Bright-red hinges on both sides allow the brace to split front-to-back, and it goes on or off in seconds. At speed, you don’t notice the low-profile STX at all. Most helmets only contact the brace at the limits of normal motion, but check compatibility with your preferred lid. Shoei, Arai and Bell helmets worked, but a deep-skirted Icon was an interference-fit. Even hanging off, the brace didn’t impede visibility through corners. It doesn’t rattle, either—nearing 170 mph on Road America’s front straight, it still stayed put.