Natural Basalt columns are attractive natural stones drilled to create overflowing water features. The hexagonal pillars have a sawn base for stability and snapped top that emphasizes the stone. Volcanic basalt oxidizes to form attractive multi-colored patina over time. Atlantic's Basalt Columns are generously core-drilled to 1.375" to fit up to 1" Sch 40 PVC or 0.75" kink-free tubing plus a light cord. A 2" diameter, 5" deep socket at the top recesses Atlantic's Fountain Light and buffers the water plume. Available in single or three piece sets for design flexibility. NBCX3 includes 3 Natural Basalt Columns includes a 18", 24", and 30" tall basalts and has an estimated weight of 367 lbs. We recommend using the FB4600 Fountain Basin, FBKIT3 Plumbing Kit, and TT2000 TT-Series Pump.