A cremation vault is required by the cemetery for all in ground cremations.  Pictured is the Ultimate Urn Vault.  Made of lightweight high-impact polystyrene, a permanent seal adhesive is used for a very secure seal in a tongue and groove edge.  This vault will protect the urn from moisture and outside intrusion to the urn while providing protection from ground sinking. 

Dimensions:  Inside Height overall: 9- 7/8" at center of vault - 7- 1/2" at sides of vault.  Any urn up to 4- 3/16" x 8- 5/8" x 9- 7/8"  will fit in this vault standing up.  Room for almost every oversized urn or two companion urns.