I bought this jacket because I wanted something lightweight that could be carried in the bottom of a backpack or in a jersey pocket for use in cold winds when I being hit or when I was caught in an unexpected downpour. What you get: - great windbreak for cold evenings - ideal for use when you get caught in a light/moderate downpour - good ventilation Don't expect: - protection from heavy rain - protection from very cold weather conditions (no insulation pads) . Conclusion: does its job perfectly. - a great backup to carry in your pocket/bag - sized to fit snugly and not sit on the body for too long. Medium is pretty good for 178cm, 73kg, 38-40 chest. PS I live in Sydney, Australia if you need a starting point for the weather conditions I am talking about.