During surgery, the breast tissue is raised to create an open pocket under the breast tissue or beneath the chest wall muscle. Inserting an implant behind each breast can increase a woman’s breast size by one or more bra cup sizes. Implants typically contain a saline solution (similar to saltwater) although in special cases the implants can contain a silicone gel. In some circumstances, particularly those in which there is breast asymmetry (uneven breast size), an inflatable implant may be used to allow the surgeon to adjust the level of inflation to attain breast symmetry and balance. Surgery typically lasts from 1 to 3 hours.