This is a set of two accurate, fluid free, ball-bearing set of two Inclinometers for measurement of spinal range of motion. Large Numbers for Easy Reading on Both Sides of the Dial. Automatic Indication of Gravity at 90º Stops for Consistent Starting Position. See Through Rotating Dial for Zeroing in Any Position. Two Adjustable Legs for Superior Stabilization on Any Part of the Body, Including Fingers and Toes. Measures All Joints of the body Quickly and Accurately. Ergonomic Shape of the Housing Connection to the Base Allows Holding the Instrument Between Two Fingers of the hand. T-track on base for Easy Attachment of an Extender or Line Laser. 5-Year Warranty Under Normal Use.