NPT CM-MRS1-4 4" x 4" Tribal Manta Ray Step Markers Black - All products are frost proof and guaranteed for the life of your pool. Shade and size variations are inherent characteristics in handcrafted tile products. Our porcelain tile swimming pool mosaics are unparalleled in quality, ease of installation and affordability. All porcelain mosaics are frost proof, maintenance free and guaranteed for the life of your pool. Vibrant colors and exquisite detail are what set our porcelain tile mosaics apart from the rest.