The armor stats are identical to those of the Demonspike Coat - a unique Full Plate Mail in Diablo I.
The characteristics of this armor are very powerful, but unfortunately, the armor is unusable for the player character (because of stat requirements in the '70s). As a result, it's just an easter egg. If you wear it through cheating, it will take away all your Agility.
The jacket doesn't have a ground frame. Therefore, when dropped from the inventory, it appears as large on the ground as it does in the inventory.