A surgical instrument is a tool or device used during a surgery or operation to perform specific actions or achieve desired results, such as modifying biological tissue or providing access for viewing it. Many different types of surgical instruments and tools have been developed over time. Some surgical instruments are intended for general use in surgery, while others are intended for a specific surgical procedure. The majority of surgical instruments are made of stainless steel. Other metals and alloys are also used, such as titanium and Vitallium. Surgical instruments make a variety of procedures and operations possible. Specialized surgical packs include the most common instruments required for specific surgeries.