Compatible with bike helmet, can be worn under the helmet when cycling in winter.

ROCKBROS helmet liner perfect for riding, skiing, snowboarding and other winter outdoor activities.

• Lightweight and soft of polyester mesh fabric to keep head breathable and cool when cycling
• Cycling cap extended visor is flippable, sun-proof and dust-proof
• Compatible as bike helmet liner absorb sweat and provide shade in the hot weather
• Multi-Functional:Fits for cycling,running,fishing,hiking and other outdoor sports
• Adjustable elastic design,one size fits for head circumference from 53 to 61cm ( 21-24inch)