Dark Bronze Double Pane Aluminum Window. Top 2/3's fixed pane bottom 1/3 opening slider. I believe it is manufactured by Milgard. It is a 4' wide by 5 tall window. Actual rough in dimensions are 47 5/8 x 59 3/4. Does have fins. The window is in pretty good shape overall. Was removed during remodel and replaced by a small bathroom window.