A pocketknife is a foldable knife with one or more blades that fold into the handle. It is also known as a jackknife (jack-knife) or a penknife, though a penknife may also be a specific kind of pocketknife. A typical blade length is 5 to 15 centimetres (2 to 6 in). Pocketknives are versatile tools, and may be used for anything from opening an envelope, to cutting twine, slicing a piece of fruit to a means of self-defence. The earliest known pocketknives date to at least the early Iron Age. A pocketknife with a bone handle was found at the Hallstatt Culture type site in Austria, dating to around 600500 BCE. Iberian folding-blade knives made by indigenous artisans and craftsmen and dating to the pre-Roman era have been found in Spain. Many folding knives from the Viking era have been found. They carried some friction binders, but more often they seem to have used folding knives that used a closure to keep the blade open. Peasant knife The peasant knife, farmer knife, or penny knife is the original and most basic design of a folding pocketknife, using a simple pivoted blade that folds in and out of the handle freely, without a backspring, slipjoint, or blade locking mechanism. The first peasant knives date to the pre-Roman era, but were not widely distributed nor affordable by most people until the advent of limited production of such knives in cutlery centers such as Sheffield, England commencing around 1650, with large-scale production starting around the year 1700 with models such as Fuller's Penny Knife and the Wharncliffe Knife.