An elogated base provided with upstanding side flanges or walls throughout its length pivotally mounting thereon a substantially correspondingly formed and sized body in parallel relation thereto having a right angularly and normally vertically disposed adjusting screw threadedly engaged with and through one free end portion bearing on an adjacent portion of the base bottom, a pointer-finger on and extended from one end of the pivotal body cooperable with a calibrated upstanding panel on the corresponding end portion of the base, and a spirit level vial fixedly seated on and disposed longitudinally of said body.
