The grenades were contained on a belt of ammunition for an automatic grenade launcher. The green metal shells are about 18.5 in long, 14.5 in high and 8.5 in wide.
Ten days after the grenades were reported lost on May 4 there is still no sign the search is over, as a group of around 100 airmen traversed the six-mile path multiple times on Friday and came back with nothing. The phrase "‘almost' only counts in horseshoes and hand grenades" probably does not apply to these particular launcher grenades, which Mountrail County Sheriff Ken Halverson has called "dangerous." He's requested that anyone in the public with information about the explosives to contact his office.
The grenades reportedly fell off of a Humvee and are meant to be used with a MK19 machine gun grenade launcher.
The Air Force Office of Special Investigations is also reportedly offering a $5,000 reward for information that leads them to the recovery of the grenades.