This universal closet door guide is for 1" to 1-3/8" thick bi-fold doors. It fits easily in the top rail of your closet door, without any tools required (YouTube videos are available if you need help with installation). Gives your closet doors a new life with a smooth glide feel powered by a dual spring loaded design that cushions doors when opening and tensions doors in closed position. We build durable, high quality parts to help you save time and money.