Valterra A01-2002BKVP Universal Gravity Inlet Hatch - Black (Carded) Lockable hatch 1-1/4" barb connection and 1/2" air vent Universal size fits both 4-1/4" W x 4-3/4" H and 4" W x 3" H cutouts Outside Dimensions: 6" W x 6-1/2" H