The ZN-9A is built on a 3/4" x 2 3/4" x 3" brass
base. Like the ZN-8A it is a low profile model with
the top edge of the fingerpieces closer to the
table. It has a total of 6 ball bearings, 3 per
lever arm. The difference between the ZN-4A
and the ZN-9A is the elimination of the bottom
bearing plate. Instead the bottom bearings are
placed inside the base, lowering the fingerpieces
by 3/16".
base. Like the ZN-8A it is a low profile model with
the top edge of the fingerpieces closer to the
table. It has a total of 6 ball bearings, 3 per
lever arm. The difference between the ZN-4A
and the ZN-9A is the elimination of the bottom
bearing plate. Instead the bottom bearings are
placed inside the base, lowering the fingerpieces
by 3/16".
