Over time, your irrigation system valve box covers are likely 2-3" below the surface. This makes them hard to find and service. I have seen suggestions of stacking two valve boxes, but this is hardly a “solution”. So here are some valve box extensions for every inch between 1" and 9" These fit my Hunter boxes but it may fit other brands too. I printed in ABS, but PETG would be OK I think. PLA would degrade over time but… Choose the best for your needs and requirements.