Dekorra Fake Rock Septic Cover Model 111 Fieldstone Overall Dimensions: 36" L x 31" W x 16" H (See inner dimensions on chart in image as rocks taper) Durable, UV protected will not fade in the sun or crack in cold weather; Commercial grade construction stands up to elements RealrockTM material provides the realistic rock features; Color may vary slightly from one rock to the next. IDEAL CONCEALING APPLICATIONS: Septic risers and manhole lids up to 30" Diam; Municpal grinder pump access ports and manholes; Commercial/Restaurant greese trap access lids; Irrigation valve box vaults and lids Lightweight, easy to move, very durable