Our patented Pop-Lock process of two equal parts snapped together is a savings to our customers on freight, storage, and delivery to the job site. The MB-8 still retains the advantages of the 18" round boxes: Tapers to Bottom, Wall Thickness is approximately 1/2", Easy to Handle, R-4 Insulating Factor, Easy to Read Meter, Easy to Adjust to Grade. The MB-8 is primarily used for larger meter sets and extremely deep frost line areas. For extra reinforcement the tongue and groove pop lock area can be riveted by either us before shipment or the customer after shipping.