SFI 24.1 Youth Race Helmets

The Snell Foundation, who traditionally conduct testing on auto racing helmets, do not test the Youth sized racing helmets.
The SFI Foundation, better known for their testing on racing fire suits, nomex racing gloves, drag race transmission blankets, etc., does perform comprehensive testing on Youth racing helmets. All helmets which pass the tests, are classified as SFI 24.1.
Only 5 manufacturers offer the youth helmets for auto racing purposes. Zamp,  RaceQuip, G-Force, Pyrotect, Bell and Simpson.
Obviously, the Youth Racing Helmet is smaller that an adult sized racing helmet. Circumference around the base of the youth helmet is approximately 31 inches in comparison to an adult x-small helmet at 36 inches.
Most Youth Race Helmets do not come pre-drilled for head and neck restraints. Although, head and neck restraints can be used. The engineers at HANS Device recommend locating the restraint anchors 5 1/2 inches forward of the rear vertical centerline. Adult helmets typically locate their anchor attachments for head and neck restraints at 6 inches forward of the rear vertical centerline. Consult your head and neck restraint instructions for properly locating the helmet's centerline.


http://www.racedaysafety.com/juniorhelmets.html