Two. Complete the shell is spherical is always off to the side and rear of the jaw. The back and neck. Open the front of the chin to the eyebrows down.
2. a full-fledged Helmet shell is a sphere close to the side and back of the neck and jaw orientation is always behind. Front opening above the brow come down enjoys end bases.
2. A full-shell helmet is a circular shape off the side and the back along his jaw and neck ALWAYS OPEN over his eyebrows back in front end all the way to his chin.