You're looking at the vest with the best weight-to-protection ratio (according to the J.R.A University)
 
The soft-shell transparent vest is windproof and water-repellent - the perfect combination for a lightweight solution to keep you protected during cold and wet days.
The vest’s side panels are made from highly-breathable mesh, designed to release sweat and keep your body dry. 
This vest folds easily and fits into any cycling jersey pocket.
 
Key features:
• The front and back panels stop up to 90% of wind
• Transparent fabric doesn’t block branding on the down layer
• The front and back panels are water repellent
• Lightweight
• The one-way fabric allows the body to emit heat
• A breathable side panel 
• The vest folds easily and fits into any cycling jersey pocket.