Strapping systems vary, and where they adjust often differs between manufacturers. Helmets with more adjustment points provide more adjustability. Check to see if the manufacturer has provided clear directions for adjusting the straps. If not, ask the retailer for more information. Fitting pads secure the helmet.
Most helmets come with fitting pads of different sizes.
Make sure there is a good selection provided with the helmet so you can add them to achieve a good fit. Styles incorporate safety and appeal. Thinshell helmets have a thin coat overlying the foam liner. Foam only helmets are made up of a foam liner and are worn with a lycra cover. If these helmets have Snell, ANSI, ASTM or CPSC safety ratings, then all provide good protection.