Three-in-one jackets provide the most for your money when it comes to purchasing protection for the outdoors. In these 3-in-1 jackets you get an outer shell that is waterproof, and breathable providing protection from wet weather and snow. The inside jacket is usually either a fleece or insulation layer that can be zipped out if the level of activity gets too high. When you stop or your body heat starts to lower, just zip your inner layer back in and get optimal warmth right away.
Lastly, you can wear the fleece or insulation jacket alone in milder weather, giving you a total of three ways to wear the three-in-one jackets. If you were to purchase each of these layers separately it would cost you twice as much. They are a great idea for anyone who needs an assortment of protection or in activities like climbing, mountaineering, skiing or hiking where weather can come in seconds without notice.