The Weight Key is a story item in Bomberman Story DS.
Description[]
It is a scroll obtained from a kid in the village of Noin Wood, as a reward for giving him 2 Mantis Arms. It details the informations about the weight order of the 5 colored bombs from light to heavy; Red (1), Yellow (2), Green (3), Cyan (4) and Purple (5). It can be checked anytime in the inventory screen.