I've added a picture of the hardware. It's from Franklin Brass and widely available online. The product is made to be an adjustable replacement cabinet pull. I replaced the stock black steel bars with sapele dowels I cut.
I struggled with that choice. I enjoy making small boxes and typically make my own pulls for those. Here I experimented with shop-made pulls, but they either looked chunky and clunky (like shop furniture) or kind of disappeared.