A Covenant Charge is a small explosive used by the Covenant on recon missions. It is able to adhere to a number of surfaces for an indefinite period of time until activated. A remote trigger is used to detonate the charge.
Zuka 'Zamamee, used such a weapon when he found Yayap and several other Grunt soldiers in Halo: The Flood. Once the Grunts were safely far away from the cage door, the Elite attached the Charge to the door. After 'Zamamee backed away he activated the remote, setting off the explosion. This broke the door lock which let all of the Grunts out of the cage.
- Halo: The Flood, page ??