A compatible replacement in case you lose the original blanks that your wireless Shure rackmount hardware comes with. I print these out of PETG, but flex filament may also work well.

Print in the orientation provided (flat side down) with no supports needed. I recommend a textured sheet and/or setting your bottom layer to be concentric for aesthetics.  10-15% grid infill works fine.

Made using FreeCAD 1.1rc3. STEP file is provided for easier modification, but can upload the FreeCAD project file(s) upon request. The tree is just poorly labeled is all.