By moving the mast toward the back of the sailboat, designers can increase the size and driving power of the more efficient foresails. The mainsail is reduced in size or eliminated altogether. An advantage of using foresails, also called staysails, is that they may be rigged for roller furling. This allows the sail(s) to quickly and easily be deployed and reefed by pulling lines. The sail rolls up around the stay. This simplicity and easy operation is one of the main attractions of the mast-aft rig.