Sets of heart-shaped steel thin die for hand roller mill die cut or electric roller mills (such as the Sizzix  Big Shot Switch )   Spellbinders and Sizzix etc.
 The tiered shapes are perfect for creating many  designs options .  
simple designs eliminate the breakage that happens with more complex designs.
Size ranges from 3 1/3 " - 1 1/2 "  and 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