A premises identification number (PIN) or location identifier (LID) is a unique code that is permanently assigned to a single physical herd location. PIN or LID registration is administered by each State and allows animal health officials to quickly and precisely identify where animals are located in the event of an animal health or food safety emergency. A PIN or LID is required to purchase official animal identification tags (840 series ID).
– USDA, Animal and Plant Health Inspection Service
Order official animal identification tags – EarTagCentral.com