If you are having less space to fix a large door for your factory or warehouse you can try for roller doors. These doors are based on concept of roll and unroll. With roller doors you are not required to have extra space for opening the vast door inside or out. You just need to push the rolling door up manually or by using electronic gadgets like motors or remote control. These doors are durable and are available in different range of materials like steel, aluminum, iron and fiber sheets. These doors work on principle of up and down opening. New improved roller doors contain a drum suspended on top which turn to roll and unroll the door at the time of opening and closure of office. Further doors sensors are an innovative technology in these doors. These sensors detect man or machine coming close to it and open automatically for it. The door will close automatically after their departure.