Helmet liners provide a thin layer between your scalp and your helmet which helps prevent irritation. And while some helmets, like ski helmets, are insulated, many are not. A helmet liner will help keep your ears warm on cold rides.

The top is mesh for breathability. It's machine washable and it can be activated.

It is designed to reduce the interior temperature around your skull during hot rides compared to using a traditional helmet. That temperature variance will be more significant in higher temperatures and can be up to 12-18 degrees cooler.

All I have to do is soak the cap in water, wring out the excess, and put it on under my hat. The instant cooling sensation is incredibly refreshing and helps keep me comfortable for hours...then just wring out the sweat, snap it 3 times and put it back on and it feels 20 degrees cooler.

There are many types, but EPS is still the choice for most bike helmets. The ideal foam would be stiffer in hard impacts, softer in lesser impacts, light, cheap, reliable to manufacture and easy to ventilate. Other materials in liners include deformable plastic constructs, air bladders and beads.

The comfort lining is the padding you feel around your head and face, which helps the helmet fit snugly and not chafe. The inner crush foam is usually made of expanded polystyrene and varies only in how many layers a helmet has.

The foam works to cushion the blow to the head, while the smooth, plastic outer shell allows your head to safely skid across the surface of impact without jerking your neck. Essentially, if you do hit your head, your helmet will take the brunt of the impact, reducing the amount of energy that collides with your head.

Helmet vents allow air to flow through the helmet, reducing heat buildup and moisture accumulation. This can help to keep the head cool and dry, increasing comfort and reducing the risk of heat-related injuries such as heat exhaustion or heat stroke.

The Four Types of Motorcycle Helmet

• Half Helmets. A half helmet is the minimum of head protection on the road.
• Full Face Helmets. A full face helmet is the most protection you can get in motorcycle headgear.
• Three-Quarter Helmets.
• Modular Helmets.

The PCM is packed into a pouch and placed between the helmet and the wearer head. The heat from the wearer head is transferred to the PCM by conduction through a heat collector which is spread over the wearer head. No electrical power supply is needed for the cooling system.

Summary: Foam is currently used for energy management in most helmets. There are many types, but EPS is still the choice for most bike helmets. The ideal foam would be stiffer in hard impacts, softer in lesser impacts, light, cheap, reliable to manufacture and easy to ventilate.

The most common option that helmets use for making the outer shell is Polycarbonate or fiberglass both of which are economical priced compared to Kevlar or carbon fibre. It must be noted that polycarbonate or fiberglass are also available in different thickness and durability configurations.

Expanded Polystyrene liner This is the helmet's most active ingredient. The liner is made from expanded polystyrene (EPS), which compresses in an impact, reducing the deceleration forces experienced by the brain.

Bicycle helmet liners are mostly molded in Expanded Polystyrene (EPS) foam. For the cheaper helmets that make up the largest part of sales in the US market, the techniques are standard ones used in the industry's "foam shops" for making all sorts of EPS parts.

Bicycle Helmet Liners: Foam and Other Materials. Summary: Foam is currently used for energy management in most helmets. There are many types, but EPS is still the choice for most bike helmets.

The PCM is packed into a pouch and placed between the helmet and the wearer head. The heat from the wearer head is transferred to the PCM by conduction through a heat collector which is spread over the wearer head. No electrical power supply is needed for the cooling system.