Armor Type: One-Hand - Poor / Epic
Level Req.: 70/80
Source: Pickpocketing/BoP Drop
Availability: Hard to come by
The Spare Hand is obtainable only via pickpocketing from creatures within Northrend and whilst there is little data on which specific mobs it comes from, Wowhead has handily provided a few suggestions.
As the item is pickpocketed, you’ll either need to be a rogue, or get a helping hand from one, if you plan on farming for it. Of course, you may find it on the Auction House occasionally, but pickpocketed items tend to be quite uncommon, so expect to hand over a lot of cash for it.
Alternatively, the Surplus Limb is a drop from Patchwerk in Naxxramas25, at a 21% drop rate. This may be easier to get your hands on in the long run.