The vinyl 4x4 Post Kit makes installation simple. Compatible with the Bolton & Yorkshire Railings each post includes a post cap and post skirt. The skirt is one-piece and should be installed over the post before installing railing sections. For 36" tall railing use 39" posts for straight runs and 45" posts for each side of the stairs. For 42" tall railing, use 45" posts for straight runs and 54" posts for each side of the stairs. The 4x4 posts sleeve may be trimmed down as needed on site. Fasteners are not included for installing to the decking or concrete surface. Additional blocking may be required.