Used worldwide for commercial and industrial applications. Extra-thick co-polymer construction wall will not warp from sun, cold, or rough handling. Unique MOLDED-IN retainers to stack boxes on top of one another. Hand-laid lid gasket seals the inside from moisture to protect gear from damage. Strong reinforced steel pin hinge system never fails. Heavy-duty steel bar latch system with locking feature keeps gear safe and secure. True square inner side walls allow gear to stack tight without shifting. Beefy carrying handle stores within lid.