This 48" single post square picnic table has a center post that is made of 6 inch square tube which makes this unit extra heavy-duty. The seat arms are 3 1/2" O.D. pipe. Copper azole micronization is an effective copper-based pressure treatment we use to preserve southern yellow pine, as it permeates the wood's cellular structure and offers durable shielding from decay and termites. This treatment is both clean and scentless, leaving no marks or irritation, and is approved by the National Association of Home Builders' Green standards. The entire frame is hot-dip galvanized after fabrication for long life. In-ground is standard on single post tables. This picnic table features a vandal-resistant design with the post being approximately 20" into a concrete poured base.