?Manufactured from ultra strong proprietary RIGID-Cast material Patented Twist-Lock fastening system – No Tools Required High 14" walls make this NuVue Products RIGID-Cast 4-in-1 Modular Garden ideal for growing a wide variety of vegetables, flowers and herbs Modular design allows for 4 different configurations BPA Free and safe for growing edible plants Weatherproof - Will not rust, mold, rot or mildew No sharp edges and bright White color