The M61 was a standardized fragmentation hand grenade utilized primarily by the United States and Canadian armed forces during the Cold War. The M61 was essentially a variant of the M26A1 production series grenade being issued by world parties in great numbers, that is, with the exception of an additional safety clip added to her design. The clip was affixed to the lever to help eliminate accidental detonations of the grenade if the base pin were inadvertently pulled. The clip came to be known as the "Jungle Clip" due to its development based on American experiences in the jungles of Vietnam during the Vietnam War. M26 grenades were prone to snagging on the jungle underbrush, causing unplanned and lethal detonations on a number of occasions. The M26 and M61 types were ultimately replaced by the more modern M67 series after the war.
Outwardly, the M61 mimicked much of the appearance of the M26 family before it. The basic design consisted of a smooth-sided case (as opposed to the famous "pineapple" grenades of World War 2) with the integrated safety pin, curved safety lever and "jungle clip". Due to the addition of the jungle pin, the operator now needed to pull the safety pin ring, then the safety clip and release the lever (also known as a "spoon") before the grenade's fuse was made active. The manual activation of the grenade initiated an internal firing pin which struck the primer within and ultimately triggered the fuse - this lasting between four and five seconds time, usually enough for the operator to throw the grenade without much fear of the enemy having time to return it.
As a fragmentation grenade, the purpose of the M61 was ultimately to detonate into metal shards and cause the most amount of concentrated carnage as possible within a dedicated area. Such a weapon could prove useful in clearing out enclosed spaces such as trenches and fox holes. The grenade was filled with 164g of Composition B filling and detonated by way of a timed friction fuse. The grenade's body, itself, provided the metal shards for fragmentation upon detonation. The grenade body held a built-in circular base which was flat along its bottom facing, allowing the grenade to be stood up on level surfaces. Overall, the grenade weighed in at 454g and sported a diameter of 57mm.
Beyond use in the United States inventory, Canadian military forces were also issued the M61 for a time until the series was upgraded and replaced with the C13 family - itself a Canadian-produced copy of the American M67.