An 8 1/2" Guarded Impactor - 7 x 12.5mm is a surgical instrument used in orthopedic procedures for driving or compacting implants, bone grafts, or other materials. The 7 x 12.5mm refers to the size of the impactor’s head, which is typically designed to fit specific implants or bone surfaces. The guarded aspect means that the instrument has a protective mechanism or design around the head, preventing inadvertent damage to surrounding tissues during the procedure.