Erza weapon schematics

This is Erza's weapon of choice. it operates in the following way. When the rigger is depressed it pushes a rod that turns a single pegged gear which moves a thin rubber block from the path of a high strength spring. The blade is resting on the spring and is thrust forward towards the target. the blade can be fired a maximum distance of 3 meters. However it is only combat effective at a distance of around 1.5 meters. The weapon is operated by swinging the lower arm around in small circles therefor swinging the chord accompanied closly by the blade, much the way a flail works.
The Weapon is incapable of puncturing armor of anysort ( with the exception of leather armor) and threfor Erza generally aims for the eyes or neck when attacking. the hidden blades is used for punturing chain mail.
when fired at ranges from 0-1 meter the Weapon can puncture flesh, break bones and puncture leather armor. at ranges from 1-2 meters it can puncture flesh and break bone. at ranges from 2-3 meters it can puncture flesh at thats it.
the blade can be fired at wooden surfaces as means of climbing them in a funtion similar to a grappling hook. however this method doesnt work on stone structures.
when the blade has not been fired it protrueds 4 inches from the end of the device makeing it in essence a smaller but still as effective hidden blade.
well, thats Erza's weapon in a nutshell and yes, it's leterally called "weapon"