The rumal is a long scarf used in India to wrap up your hair - like a bandana or a sort of turban.
The thuggees, highway bandits who worshipped the goddess Kali, were famous for using their rumals to strangle their ritual victims. A coin was tied or sewn into one end of the rumal, which was usually about two feet long. The thuggee would swing the weighted end of the rumal around their victim's neck and dextrously grab it, strangling them before they could cry out.