‌A 4-level flow rack designed to efficiently store and automatically advance materials down gravity-fed lanes. This rack holds 6 different part numbers, indexed to make it easy to pick parts from bins on lower levels. Pick lights provide a visual indicator for what to pick, with verification that the item was picked using the pick light curtain. This rack design also includes a bottom return lane for empty tote bins, optimizing space and improving the ease of access for picking operations.