all hemets sold in america are required to pass CPSC testing standards.
the SNELL designation used to carry more weight; the current bicycle helmet SNELL standards are very close to the CPSC standards.
SNELL is voluntary, however, and helmets subject to this scrutiny are still considered to be the better, 'stronger' helmets. Specialized helmets are some, even their 40 dollar helmets are SNELL certified.l