Washing Machine Outlet Box

I recently bought a shower panel for a bathroom remodel. Needed a washing machine outlet box that would fit the narrower profile of the shower panel. I found that it was cheaper to buy a standard outlet box and harvest the valves than to purchase a purpose made narrow outlet box. Post printing, I sprayed a liquid rubber sealant coating on the interior to ensure a watertight box. The valve holes are 0.75 inches in diameter. The box is just larger than a 2x4 depth to accommodate drywall.