A mock rock drops over a backflow preventer, valve manifold, or well head to conceal it while keeping it accessible — measure the footprint and height of what you are covering, then pick a rock with a couple inches of clearance all around. Raised garden beds lift planting out of poor soil; galvanized steel beds resist rot and last far longer than wood outdoors, and taller beds give roots more room.
A mock rock sized to clear the unit conceals it while staying removable for service. Measure the backflow preventer or valve manifold — including any pipes or handles that stick up — before choosing one.
Measure the length, width, and height of the equipment, then choose a rock with at least a couple inches of clearance on every side so it sits over the unit without resting on it.
Galvanized steel beds do not rot, warp, or need sealing like wood, so they last many seasons outdoors. Pick bed height by what you are growing — deeper for root vegetables.