The Fox Racing Baseframe Pro was designed to be worn beneath your jersey for low profile coverage that guards against roost without restricting your ride but can also be worn with a roost deflector for maximum protection. The Baseframe Pro has removable sleeves, creating a modular design that allows you to customize your level of coverage. The shirt's impact absorbing foam is body heat activated meaning it softens to conform to your body for added comfort. Furthering that comfort, the Baseframe Pro also utilizes open stretch mesh in key areas for increased ventilation.