This is a sweet weapon. One has to see it in action to believe it. The is a 'sword' though I might call it a metal whip. The blade of the urumi is constructed of flexible steel such that the blade is in motion like a whip when used. It has a hilt with a cross guard. It is very difficult to master and is used similar to a flail (though requires less energy). There can be a single blade or numerous blades. The Sri Lankan version had 32 blades.
I would imagine there is a great chance of injuring oneself when using this unless very well trained.