From A&F:

All Raw Steel kits are light weight and made from our exclusive Raw Steel shells, patented Raw Brass Lugs/Hardware, Whiskey Maple Hoops, and Remo Heads. We cut, roll, and weld the shells, cut straight 45 Degree edges, then leave them in their complete raw state.  The Raw Steel Kits are dryer then our Royal and Copper kits, not loud by any means but tune lower then their sizes and have a perfect balance between punch, warmth, and attack.  A sound engineers dream, they are extremely microphone friendly!