Nunchaku (4e Equipment)
From D&D Wiki
 Military Melee Weapons
|Nunchaku||+3||1d6||—||15 gp||2 lb.||Flail||Off-hand|
A nunchaku is essentially two rounded wood or steel bars attached by a short length of chain or heavy cord. It's not as lethal as other flail-type weapons, but in the hands of a master it is an extremely difficult weapon to defend against.