MD2 is Malkoff's small light - 2 x 123 or 1 x 18650. Takes all his Surefire dropins - M30/M60/MC-E.
Cool feature is the optional brass dropin retaining ring which provides a 2 stage function with a twist of the head.
Simple little light. Similar to a 6P. First impression was it seemed a bit cheap. Now I feel stupid for thinking that and appreciate it's design.