Needle weapons are a silent and deadly ranged weapon that uses both laser power and needles crafted from a form of crystallised neurotoxin to kill or its targets. The weapon fires a laser bolt like the Lasgun to propel the toxic sliver and penetrate any armour. A millisecond after, it fires the needle. The laser bolt melts and cuts through armour, leaving the skin (or other vulnerable parts) exposed for the needle, which knocks out or kills the target with a virulent neurotoxin. A Needler is a silent weapon and the needle of neurotoxin is so fine that its target often does not even feel it penetrate his or her flesh.The crystallised toxin dissolves immediately upon contact, is extremely fast-acting and takes effect almost immediately. The laser component of the Needler operates on an invisible wavelength of light and thus cannot give away the positon of its user. A multitude of different toxins can be used with a Needler, though the most common are deadly neurotoxins, sedatives which only render the target unconscious and intoxicants which can stupefy the target or make him amenable to interrogation without rendering him fully unconscious. A Needler is a valuable weapon which needs specialised ammunition and maintenance -- even more so than the Sniper Rifle Lasgun -- and is therefore usually reserved for elite sniper units of the Imperial Guard or the shadowy Assassins of the Officio Assassinorum.
These are highly specialised side arms and are very rare in the Underhive. They are only ever rarely found in the bazaars of the Underhive who deal with exotic items. Needle Pistols are prized mainly due to their silence as they are weapons primarily made for assassins. Also the toxic needles are able to bring down the toughest opponent with the equal ease of bringing down a weaker foe.