Urethane is a plastic that gives a slight bit while you press against it. Works to press metal into when you are forming metal with a bracelet former kit or mushroom former. Urethane comes in various durometers of softness/hardness. It is also sold with containers and pushers.
Bag of 10 pieces of urethane for use with impression dies. 95 durometer sheet. Pieces range from approximately 1/2 inch to 1 inch in length. Thickness of each piece is 1/4 inch.
Note: These will fray, crack and deform with use, but you will get many uses from them.