The Ballenger knife STR (straight) is a surgical instrument used in ENT and nasal surgeries to precisely cut and shape cartilage and bone. Its main uses include performing submucous resections of the nasal septum, correcting deviated septums, and refining nasal contours during procedures like rhinoplasty. The key feature is a 360-degree rotating tip, which allows for intricate, controlled cuts without repositioning the surgeon's hand.