Alpha Direct is my go-to mid-layer insulating fabric. My testing shows that two layers of 60 gsm Alpha Direct have the best warmth-to-weight ratio of any Alpha Direct fabric. I asked Farpointe to make me one, and now the Farpointe Alpha Duo is a standard product for them. I only wear it when temps are less than 15 °F. Otherwise, a single 60 gsm layer is sufficient. – Stephen Seeber