The ZN-9+ (ZN-9 plus) with 1/2" OTO has replaced the ZN-9. It is built on a 3 1/2" x 3" x 1" steel base and weighs 3.25 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 1/2". The lever arms have a parallel arrangement and the OTO cannot be changed.
The ZN-9+ comes standard in Black finish. Optional colors as shown on the ZN-9RZ are $20 extra.