Tranquil Decor Real Basalt columns have unmatched simple beauty. Perfect for creating a bubbling feature in a landscape or indoors, these columns will provide years of enjoyment. Each column is core drilled with 1 1/4" (32mm) hole from end to end, the last 1 1/2" is enlarged to 1 3/8" (37mm) to house optional light ring. Basalts can be used individually or in sets. Three column sets are available. Natural cut sides with polished end make for a beautiful display even if the pump is off.