Here’s Devotion’s classic Frejus with a Cinelli adjustable stem. Titan also made a similar quill and the idea was that rather than making multiple stem lengths, you just make one that’s adjustable for different rider’s specifications.
Sexy as hell and a bit pricey for NOS and used they fetch upwards of $200 USD. Even though it’s vastly inferior to today’s threadless stems in terms of stiffness, the old school track nuts go bonkers over them.
Eventually they just made varying lengths, as evident in my old Titan bar / stem combo that was on my Higgins.