This is a multi-material remix of RyanResolution's Clapper Slate (Thingiverse thing:1463739) for printers that can print with two different filaments. It prints as one piece and requires no assembly.

The color changes happen 1 layer (0.2 mm) above the previous top surface, to avoid that the nozzle with black color will travel over the white surface and leave black streaks.

Next to splitting it into two materials, I also tweaked the model a bit:

• Narrower gap for the clapper to increase the surface area where the two parts touch, this should make it somewhat louder (although it still isn't perfect, it still only really touches at the end)
• Removed the tiny overhanging part
• Made top ‘clapper’ part a bit less thick
• Bigger font to reduce risk of incompletely printed letters
• Made the hinge a bit more sturdy and slightly tighter (tolerance is now 0.3 mm).

This is only the smaller one, I didn't do the XL because it is too large for my printer.

A single-material STL is also available should you want to print this tweaked model in a single material or rely on filament swapping at certain layer heights.

No supports are required.
To break the hinge loose, I shoved a sheet of cut-up blister packaging in between the gaps.