Horizontal Urn Vault from the Millennial series. This top seal unit is made of lightweight high-impact polystyrene. It weighs 8 pounds. The outside measures:10 "Hx13.5" W x18.5 L. The narrow inside measures: 9.5" H x10.25 "W X 15"L. The wide Inside measures: 8.75"H x11.5 X 16.25"L. When choosing a vault the inside measurements are the most important so that your urn fits inside and the top can go on and be sealed. The outside of the urn must fit into the inside of the vault. Contact Lovedonesurns for assistance when placing an order for any vault and we will assist you so that you get the correct size vault. Our toll-free number is 1-877-236-7615.