This item is a bargain version of the Emergency Contact Key Chain/Pendant Shell and Insert (http://shpws.me/J3Fo and http://shpws.me/EA1G). You lose the contrasting colors but avoid the per piece charge of ordering two separate items.
The intent is for emergency information to be supplied when removing and opening the hinged insert. For darker colored inserts, you will need to apply a label (1/2" wide) for this purpose. For lighter colored inserts, you may write the emergency information directly on the interior of the insert with a permanent marker. The clasp is designed for use in two different directions allowing ease of use as a key chain or pendant.
It is your responsibility to be familiar with the the nature and required treatment of the materials you select. Models containing small parts (including the assembly) should be kept away from children.