Above Floor pool elements have been at 1 time made entirely of metal or steel alloys. These days, the pool partitions remain steel but today company's like Doughboy and Wilbar (Seaspray Pools) are working with resin factors in many of their versions to increase their strength, sturdiness and item longevity. https://www.profi-poolwelt.de/3-60-x-1-25-m-aufstellpool.html