The Snorkel® Vault Extension allows you to increase the installation depth of your wetland filter without losing convenient surface access for maintenance. By securely locking onto the top of the Snorkel Vault, using one or more extensions allows for deeper excavation depths, ideal when adding extra layers of gravel or stacking additional FilterBlox™ Modules for higher-capacity filtration. It is built from the same rugged, rotationally molded material, giving it the strength to support the weight of stone, gravel, and foot traffic above.