Smooth rails across the top and bottom.  Meets BOCA code for pools.  Ships fully assembled in “six foot” wide panels. Actual panel dimensions are 71 3/8” widths, creating 73 3/8” wide panels on center when installed. Panels include (15) 5/8” square pickets and horizontal channels measuring 1” x 1 1/8”.  Standard picket spacing is 4 ½” on center, providing 3 7/8” air space between pickets.