Claymore Mine - An antipersonnel mine that uses C-4 plastic explosive to spray 700 steel ball bearings in a 60 degree arc, with a 50 meter wide killing zone at 50 meters out. Electrically detonated and used primarily for perimeter defense and ambushes. For more specific details, check out this excellent site:  http://www.armystudyguide.com/m18a1/