The Fox Baseframe Pro SL Vest is a breathable base layer with built in guardson the chest.  Designed to be worn under your jersey for low-profile coverage. Designed as an unrestrictive protective base layer to be worn under jerseys.  Fox Baseframe Pro SL Vest Features Minimal restrictions - maximized benifits Impact absorbing F3 provides full coverage and unrestricted range of motion Large perforation and flex grooves in the back foam contours and flexes with rider movement Body heat activates the polymer to conform to body Moisture wicking, open stretch mesh for breathability Built in padding at hips offers additional comfort F3 back insert is removable for easy washing