These back rest mounting brackets are made to mount on top of your transom or your flats boat deck. A 3” x 4.5” x 3/8” anodized pad is screwed to the horizontal surface and the L shaped back rest arm is attached with a black hand knob. When the arms are removed from the pad, they can be folded parallel to the cushion for storage, leaving nothing but the flat pad. The brackets come in short and long lengths and are made of 2” x 1/2” radius flat bar. The arms pivot on 4 1/2” white Delrin discs. The long arms are 16” high and are great for flats boats. The short arms are 9” tall, and are for use on top of a transom with our rear bench seats. Complete with cushion.