Last year, Samsung let us customize the hinge cover for the Galaxy Z Fold 2 and it has now extended the idea with the Galaxy Z Flip 3 Bespoke Edition. The Galaxy Watch 4 is joining in as well, but not the Z Fold 3 unfortunately.
As the name says, this lets you customize the color scheme of your phone in any way you want, including the color of the hinge. You can also pick separate colors for the top and bottom halves of the rear panel. Right now you can pick between Black, Yellow, Pink, Blue, and White. The hinge can be swapped between Black and Silver colors.
The camera cutout will remain the same no matter what color you pick.
Right now, the Bespoke Studio only serves in markets including the US, the UK, Canada, Australia, France, and South Korea. Samsung plans to expand this list eventually. Note that the pricing for all Bespoke models is the same as the original devices. The Bespoke Edition phones and watches will also come in a slightly different case.
As for the Galaxy Watch 4, you can pick between several strap designs and colors for all the watch sizes, but the watch faces will remain the same.