A Type I hardhat provides for protection from blows to the top of the head ONLY based on standards provided by ANSI/ISEA in the United States. These hardhats typically have a strap suspension inside, but this is not always the case.
A Type II hardhat provides for protection from blows to both the top and to the sides of the head based on standards provided by ANSI/ISEA in the United States. These hardhats typically have a foam insert to allow for side impact protection.