Jack O'Neill's knife embedded in the center of Heru'ur's left hand.
A combat knife is a knife for combat. It is generally carried by SGC personal and is able to pass through Goa'uld personal shields. (SG1: "Secrets")
The combat knife is also issued to Phoenix team member's base kits. (RPG: "Core Rulebook")
Colonel Jack O'Neill threw the knife at Heru'ur's Kara kesh, disrupting his personal force field and forcing him and his Jaffa to retreat from Abydos to the Ha'tak. (SG1: "Secrets")