Determine your mailbox dimensions after ordering. Let us know the letter height you want (The maximum height you will specify cannot be more than 6 inches.) The mailbox number you specified will be sent as 1 piece of Silver reflective and ready to use. It is self adhesive. The surface to be bonded must be dry and clean. It is not applied in rainy weather. Sunny weather should be preferred for better quality of adhesion. It is resistant to rain and outdoor weather conditions. Follow the instructions to paste the product.