O2 Rainwear Calhoun Jacket. If you ride long distances or train consistently in adverse conditions, then you'll appreciate the streamlined fit and weatherproof protection of the Calhoun cycling jacket. Innovative ripstop fabric blocks wind and water while allowing your skin to breathe. Form fit design increases aerodynamics, pit zips circulate cool air, reflective elements enhance safety and waterproof chest pocket holds essentials. Super compact design packs up easily inside your backpack or bike bag.