The roller arm stay is used to restrict the opening of light to medium weight bottom hung fan light windows and side hung windows. Fitted with a brass roller ensuring longevity in service unlike the cheaper plastic rollers. The roller is plated to match the arm finish. The stay can be used individually or in pairs depending on width of window. Rollers hang vertically when the window is closed. These products are not handed. Comes with a 10 year mechanical guarantee. Suitable for domestic use.