The mortise lock for narrow stile doors ES 958 with profile cylinder hole is ideal for use in tubular frame doors made from metal or plastic. This mortise lock is particularly robust and durable due to the high-quality stainless steel. The lock is suitable for both right-opening and left-opening tubular frame doors. Of course, it is also tested in accordance with DIN 18251-2, Class 1, and therefore meets all the mortise lock requirements for tubular frame doors.