Belay Jackets are specifically designed for climbers but also work well for other outdoor winter activities. Mountaineering and Ice Climbers generate heat when moving. When you are belaying you are not moving, so you throw on your insulated belay jacket over your normal layers for instant warmth. Belay Jackets work really well with soft shell jackets.
Belay Jackets typically have a water resistant outer fabric, and synthetic insulation. They should have a large hood that will fit comfortably over climbing helmets and the hood should cinch down to give superb cover in foul weather.
Below are the most popular Belay Jackets as indicated by GearBuyer.com.