Good for basic no frills measuring of pipe of small irregularly shaped objects. I used it to measure the diameter of tail pipe on cars and for the interior dimensions of some rubber hose when I was unsure how big it was. Very cheap, less that $2. Made of plastic and not very sturdy, but for quick and dirty shop measurements it is more than accurate enough and who cares if you accidently drop a three pound hammer on it. I've got a couple and keep on in the tool box out in the car.