Your Chest Number is equipped with the electronic timing chip. Do not remove it and use it on your chest only. Do not fold, do not knead, do not peel off the sticker from the chip and do not remove the spacer foam for proper operation. 1. Let your NUMBER ALWAYS ON THE CHEST. DO NOT COVER IT with blouse, jacket, backpack strap etc. 2. Do not put your arms above your chest number on the checkpoints zones. 3. Do not attach your chest number on your body's sides (legs, p.e.). 4. Do not cover your chest number with blouses, jackets or other clothes.