The Swarm Winter Jacket is purpose-built to be worn under a riding jacket on a motorcycle, so that you never need to slow down when the temperature goes down.
To stay warm when riding in winter, the trick is to layer-up and block body heat by using slim, light but insulated layers. The Swarm Winter Jacket is equipped with an extremely lightweight and insulated Dupont Sorona fill and has a slim fit so you can wear it under your riding jacket.