High Density Storage and Filing Files + Storage by Mayline Can be easily installed on existing 4-Post shelving including most competitive shelving lines. Approximately 10 minutes to install. Do not need to remove existing files. Housing adds 8 1/4″ in height and 11 1/2″ in depth. Extends 4-Post shelving out by 2″. Note: Security Shade cannot be used in conjunction with a Reference Shelf.