Made of flexible polypropylene material that will not break and resist crushing. This crown and bridge box has a positive lock-in mechanism. Top and bottom connect with a flexible hinge. It is an attractive crown and bridge tooth box that is available in a wide variety of fun colors to work with. Available either in plain, already approved artwork or custom printing. For custom printing the one time $35.00 dollar die charge covers the cost of preparing the metal die, which is retained in our files for repeat orders.