Die cut thin metal  flower shapes . Steel thin die cut  for hand roller mills or electric roller mills (such as the Sizzix  Big Shot Switch )  Spellbinders and Sizzix etc.
 The tiered shapes are perfect for creating many design options.  
simple designs eliminate the breakage that happens with more complex designs.
size ranges from 2 1/2 " - 1 1/4 " these will then shrink to half that size 
 
Here is a link on how to successfully use the die cuts in a Sizzix machine.
https://vimeo.com/737292992