Leather is an entirely different material. Although it is well-known for its style and protection feature, but Kevlar motorcycle shirts are not made of it. It is the flannel that makes these shirts cool and distinctive. Flannel is a soft fabric that is either made from synthetic fiber, cotton or wool. It might not have that shiny surface like that of leather but it is much lighter and suitable for even summer days. So, it is best to wear flannel shirt instead of leather jacket while riding your bike in intense sunlight.flannel motorcycle jacket