Made of high quality polyester 100% fully embroidered How to Iron: Heat the iron to a moderately high temperature that would not burn the fabric. (You can put cotton fabric on the patch to secure the cloth before ironing. ) Place the patch in the desired position & place a pressing cloth (handkerchief or pillowcase) on top to protect the patch. Press the iron down for 15-30 seconds, depending on the fabric iron from the front for 1-2 minutes, the main position are edges and corners Let sit for 1-2 minutes until fabric is no longer hot. Sewing: For some backpacks, hats, and heavy fabrics the iron-on method may not work well with heavy materials. If that is the case consider machine or hand sewing them on.