Choose between High Impact Polystyrene or Premium ACM (Aluminum Composite Aluminum) materials. Each panel and rider are digitally printed, have 4 holes, and are coated with a clear UV laminate for extra protection. All panels 18x24 or larger include 2 top grommets for reinforced hanging durability. Add "Shield Protector" and your panels will be graffiti resistant and last up to two years longer.