Sturdy + Stackable: Durable Auto-Lock Latches Make Connecting These Stackable Units Quick And Easy Quick Access: The Quick-Release On The Locking Latch Allows You To Easily Separate Each Module When Stacked For Quick Access To Individual Units Portable Convenience: Steer This Wheeled Unit Using The Ergonomic, Telescoping Handle Secure + Easy: Toggle Latches Securely Close And Lock Lids Of Shallow And Deep Toolboxes, And Are Easy To Operate