This is a very rare example of one example in the series of short-lived Accuracy Systems Mini frag. One of three cylindrical variations designated as the M560, this is the shortest of the group. All of the types were developed in the mid-1980s, and were intended for use by US Special Operations Forces. They were made using two halves with internal fragmentation designs, which were then welded together. The Dutch V-40 mini had been very popular during Vietnam and afterwards, so this was an attempt to replace it with a more modern design.
This example is in the typical camouflage paint configuration. The inert fuse unscrews correctly to examine the grenade interior. The company itself was involved in legal troubles shortly after developing.