One of the characteristics of fine bikes is a lack of stuff clamped on all over. There are brazed-on fittings for everything required.
I often take a busy bike path out of town on my rides. So I decided to mount a bell on my new bike to warn pedestrians and slower riders. Of course, I chose one of those lovely Japanese brass bells. But how to mount one without a clamp? The French constructeurs tapped the bike's stem and screwed in the bell. I wasn't willing to do that to my Nitto Pearl stem. My solution was to make a headset spacer mount that the bell screws into.
The bell mount is 10mm thick. The bell itself is not included.