MLB is short for Mini Long Board.
The Kazuma version adds another level of performance to what you would normally expect from a typical longboard. 
A relaxed entry rocker allows for maximum paddle power and short nose rides and the high performance tail rocker and Double Barrel concave will give you a shortboard ride and feel when surfing off the tail. 
The MLB works well if you want more performance form a "longboard" or if you are a lighter surfer looking for an easier to ride longboard replacement.
If you feel like a normal longboard is just too much board, the MLB is just the board for you.