The Metro SMA21A-ADD is a versatile shelving unit accessory designed for efficient organization. This Quick Ship SmartLeverâ„¢ 21" Single Arm features a robust SmartLever Arm with an integrated ArmKeeper for secure support. Included are four shelf mount hooks that allow for easy attachment and customization of your shelving setup. Additionally, four locking wedges ensure stability and safety, making this unit NSF certified for quality assurance. Ideal for maximizing storage space in commercial and industrial environments.