This is a spring-loaded 7/8 in. diameter nylon roller guide in a steel nail down base. The base is 3/8 in. with 2 nail down tabs on either side. It mounts on the top edge of a bi-fold door that is 1 in. to 1-3/8 in. thick and up to 30 lbs.
May cause Cancer and/or Reproductive Harm - www.P65Warnings.ca.gov