The Hydra Pools 50830 is a 18' 2" x 36' 8" Roman 6" Radius with 8'Res. Inside and out, only the finest goes into Hydra Pools®. Their precision engineering means that every part is meticulously designed and fabricated for flawless fit and finish. The strength of Hydra's intelligent design means you will have a swimming pool that you can enjoy trouble-free for years to come.