Radiant Pools PM2152TC-IG 21' Metric Round Embossed Quartz In-Ground Pool with 52" Wall - This Radiant Pools Metric Series in-ground pool features a round shape and 52" wall. Engineered from technology developed for the NASA Space Program, Radiant Pools are the only structurally insulated swimming pools manufactured using an R-10 insulated panel. Our walls are more durable than steel, polymer, and even 12" of concrete. Our 2" thick wall panels are constructed of an EPS (expanded polystyrene) foam insulation core bonded between sheets of durable acrylic-coated aluminum.