Radio speaker feet (pads)

I'd like to add four of those little rubber "feet" things to
the external speaker of my R75. I'm pretty sure such
an item is available, but I'd have no idea what section of
Home Depot to look in... if that's where to get them.
They're about a quarter inch high and 3/8 inch across.
Lot's of speakers or stands come with them ready to
add, but my speaker didn't.
Any suggestions what and where I should look?