
The wire strings pass through the Truitt levers up to the tuning pins. The tuning pins for the row on the other side are visible.
My new Argent Fox double strung wire harp has a full set of Truitt sharping levers with delrin fret pins.
Here are some photos of them on my harp!
A nice, brief article introducing the concept of levers:

A view from underneath showing the Truitt levers on both sides of the neck for both rows of strings.