The troy lee d2 full face helmet the d2 is the benchmark in the full face bicycle helmet market with its legendary tld style this helmet has been the choice of more championship winning riders than any other astonishingly light in weight and incredibly strong the d2 is the perfect helmet for bmx mountain biking and even other action sports like snowboarding this yeariacutes d2 features all new designs with the same protection and comfort features that made it so popular troy lee