This Rail Installation Kit is suitable for use with both 12" Balustrades. This installation kit connects both ends of one 12" top or bottom rail to 13" newel posts only. Two kits are needed to accommodate a top and bottom rail. Rail Installation Kits are crafted in urethane, a high-density, non-porous material that offers an enduring resistance against damage caused by water, so the parts will not corrode like metal can or decay like wood. Our balustrade product selection includes both large items and smaller finishing touches.