Not too big and not too small, the expandability of the Pondless® Waterfall Vault makes this filter perfectly sized to meet the need of any Pondless® Waterfall and to fit easily with AquaBlox®. Simple to install and maintain and easy to camouflage Built-in water inspection port for easy access even when buried Large interior fits a wide range of pump sizes up to 10,000gph Expandable height makes Pondless® Waterfall Vault fit any size project Comes standard for use with the Small AquaBlox® Made from durable rotationally molded polyethylene Vault measures 23"L x 17"W x 25.5"H Extension measures 16"L x 16"W x 9"H Vault opening measures 16"L x 16"W The optional Pondless® Waterfall Extension slides onto the Pondless® Waterfall Vault, increasing the height for deeper basins using the Large AquaBlox®. It is required when using larger and/or taller pumps with 3" plumbing (to ensure the height of the vault is tall enough to accomodate the large pump). SKU 49000 49001 UPC Code 827807490007 827807490014 Description Pondless® Waterfall Vault Pondless® Waterfall Vault Extension