MS-840-PF is a type of sliding door used in Miyama-brand residential and commercial buildings. It is a double-acting sliding door, which is intended to both open and close with the same action. The MS-840-PF is constructed with heavy-gauge steel frames and strong plastic panels, making it a very durable and long-lasting product. It also features latches and locks for added security. Its overall design is simple yet elegant and can match any interior décor.