Quick Ship - "S"Hook for MetroMax® i or MetroMaxQ™, connects add-on units to starter units, used for end-to-end configurations (collar-to-collar connection), (2) required per storage level, also used with MetroMaxQ™ for right angle configurations (Use (1) M9995 + (1) Q9995Z) per storage level, NSF, Note: collar plug provided fits MetroMax® i only