The Prizm Technical womens snowmobile jackets and pants are a shell only that includes a mesh liner, giving the inside of the jacket a finished look. A next-to-skin base layer like DSGs D-tech line is recommended for any tech shell jacket and pants. In extremely cold conditions and in the morning while heading up the mountain, a mid-layer is recommended as well. The fit on these jackets accommodates base layers, but you should order the size you regularly wear. Finally, you are sure to enjoy your snowmobile trip when you are dry and comfortable, so do yourself a favor and buy the highest quality womens snowmobile gear available from DSG Outerwear!