carpentry: measuring and marking tools 
Instrument consisting of a cord that rewinds into a case filled with chalk powder; it is used for marking straight lines.
Metal body housing the chalk powder and the line.
Curved metal end of the cord that can be attached to an object; it also makes unwinding easier.
Chalk-covered cord that is pulled between two points to mark a straight line.
Device for rewinding the line into the case containing the chalk powder.