Guardhouse Display Boxes#: GH-SLAB-W20. Size: 11x5x4 Color: Select Below. Sold Individually. This sturdy wood display coin slab box beautifully accommodates 20 NGC or PCGS certified coins. Built with foam inserts for easier handling of the 20 coin slabs, this Guardhouse box is made of genuine wood and has felt interiors. Its strong gold colored hinges ensure the box a long life.