What post sizes do post wraps fit for RDI® Vinyl Railing?

RDI Railing’s 4″ x 4″ adjustable vinyl post wraps are designed to fit posts ranging from 3 3/8″ to 4 1/8″ in size. In addition, RDI Railing’s 6″ x 6″ adjustable vinyl post wraps are designed to fit posts ranging from 5 7/16″ to 6 1/8″ in size.