This very rare Leedy & Ludwig tuning bar would allow professional tuners to establish a true A 440hz. So much that they guarantee an absolute A 440hz @74degree temp, as marked. The hollow box measures 11”x 3.5”. The silver nib is taped by hand allowing the rubber mallet to tap the aluminum bar at a perfect A. One of the Bakelite fasteners has cracked but otherwise condition is very good and fully functional.