You will receive 20 x 16mm silver plate round cinch mount cabochon or coin settings. (Ten settings).
 
Please ensure you cinch the tops together.  If you just slip a sixpence (or cabochon) into the setting, it will fall out.  It has to be secured shut with your pliers.
 
Also available in 20mm and 18mm and also the larger 28mm & 30mm.  The necklace you see is an example of what a cabochon looks like in this excellent setting.