Nicolock Nicostone THMTRBL1248 12" x 48" Bluestone Thermal Tread Paver. Give patios, pools and entryways a whole new look with the smooth surface of our thermal-finished treads. These caps can be used with most of Nicolock’s outdoor stone steps and paver stones. Adding them increases the height of the step by 2 inches, providing a finished look with a bit of overhang.