The NFL replica speed helmet size medium is 12.75 (L), 9.25 (W), and 9.75 (H). NFL speed replica helmet in full size. Made of plastic. Each year in the United States, more than 100 people die and over 8,000 are injured when using motorcycle helmets that are not appropriate for their age or skill level. Motorcycle riders under the age of 25 should wear a helmet at all times. Adult riders of any age should wear a helmet whenever they ride motorcycles. Even if you have had no previous head injuries, you should still wear a helmet because even healthy brains can be hurt by serious collisions with objects such as tree trunks or highway signs. A helmet will keep you safer on your bike. There are many different types of sports helmets available today. Sports helmets can be divided up into three main categories: hard hats, soft helmets, and hybrid helmets. Hard hat safety helmets are made out of a durable material that provides protection against cuts and abrasions. These helmets fit tightly on the head and are usually worn by workers who may be exposed to heavy machinery or other elements. Soft sport helmets are designed to absorb some of the impact of falls that might cause injury. These helmets typically contain multiple layers of materials that work together to cushion the head during impacts.