The ZN-9ZX 5/8"OTO is built on a 3 1/4" x 3" x 1" steel base and weighs 2.98 pounds. It features 3 ball bearing per lever arm, magnetic return, solid silver contact points and very fine threaded magnet and contact screws (56 TPI). All screws are stainless steel. The OTO ( outside to outside dimension of the fingerpieces) is 5/8". The lever arms have a parallel arrangement and the OTO cannot be changed. The ZN-9ZX is available in BLACK finish only.