The Small Pillar Mount is intended for columns ranging in size from 12- 30 in Circumference (4 - 10 Diameter.) and can be used on square or rectangular columns with sides greater than or equal to 4 inches in width.
The Large Pillar Mount is intended for columns ranging in size from 30 - 144 in Circumference (10 - 46 Diameter.) and can be used on square or rectangular columns with sides greater than or equal to 8 inches in width.