Mac in a sac - Polar Trendy reversible jackets made from RDS-certified down for the transitional season. When it's still too warm for a winter jacket but already too cold for a sweat jacket, this lightweight reversible down jacket comes into its own. It provides cosy warmth and is still light as a feather. If it gets too warm when you're out and about, it can be stuffed into the practical drawstring bag and takes up hardly any space.