Four extra-deep base-to-lid locking cleats that ensure maximum stacking stability Two Integrated Automatic Pressure Equalization Valves Two rugged double-wide handles Wide-track polyurethane wheels with ball bearings and nylon hubs Open cell core, polymer wall construction Stainless steel hardware and padlock protectors 6-piece foam set Personalized nameplate service available Lifetime Guarantee of Excellence Watertight, crushproof and dustproof O-ring seal