PLYLOX window clips securely attach to 1/2" plywood which the fits into exterior window casings.PLYLOX window clips create rigid, safe, temporary attachment of plywood to brick, wood, or stuccoNo nails, screws, bolts or brackets will permanently damage your property.PLYLOX window clips holds plywood in window casings as well or better than any other hardware.PLYLOX window clips are rugged and will last year after year. If you move, take them with you.