Product Description: The Model 3-R Spacer is 7.5 square and the base is gently rounded to prevent gouging the roof. The outer edges are raised 2" and increased elevations may be achieved by stacking Model 3-R-2 or 3-R-4 on 1 or 2 spacers, each with a height of 2". Four drainage ports are provided to prevent ponding within the device. The dimensional area resting on the roof is 7.5 inches square and 52.56 square inches exist of contact roof support.