Th Marine Automatic Aerator ControlProvides a source of oxygen rich water to your live well automatically. This unit features a solid state timer with adjustable off times to adjust to varying conditions. Easily adaptable to existing systems. Front panel is 3 1 4" x 3 1 4" and requires only 3" behind panel. This is the only timer on the market that will handle a high capacity pumps current draw. 10 amps. Mtg Hole : 3" Round 2 1 2" Square