Such a device is useful in making compound bends in electrical conduit to ensure that the bends keep {TAIL ~ each end} of the conduit in {HEAD ~ a common, or vertical plane} 
Such a device is useful in making compound bends in electrical conduit to ensure that the bends keep { TAIL ~ each end } of the conduit in { HEAD ~ a common , or vertical plane }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD