Nothing compares to the flexibility, durability and savings of the Duo-Flip system.  In moments, you can have any possible combination of ID numbers, then flip to display the corresponding placard.  Self-contained placards easily fold over four aluminum hinges.  Four stainless steel fasteners lock your chosen combination securely in place.  Standard Duo-Flip systems contain three or more panels in one frame.  The unique deep-formed aluminum frame provides maximum wind protection and stability.  Duo-Flip is approved for use by private and fleet carriers.