To answer your question, yes we are talking under armor. The cold weather stuff is great. My favorite fishing season is during the winter and here in Idaho it can get pretty chilly. I start with under armor both top and bottom. Then its a mid to heavy fleece pant, a light cotton long sleeve, fleece jacket and I top it off with my waders and a soft-shell. For days with heavy weather I wear my gore-tex shell. For socks, i prefer mid-weight Merino wool. I have found that it is better to have room for circulation rather than wearing a bulky winter sock. My $.02 hope this helps.