The ZED decvice is a weapon that came with this "Twisted Christmas" Update 2012. It's weight is 8lbs and it's cost is 2000£. It is one of the three "Perk Neutral" items. It's full name is "Zed Eradication Device" so the correct term would be ZED, but idc.

It is capable of various things such as:

• Shooting plasma balls
  
• Shooting a "Stasis Link" which will slow and confuse ZEDs, make them also more vulnerable and disable their abilities.
  
• Locating Enemies on a radar in 40m range.

It's magazine size is 100 energy units, and you can carry a total of 400 units with you. Each magazine has a cost of 100£.
The gun is equipped with a green laser dot, similar to the M14 EBR. It doesn't have any other sights.

Which Perk is the best for this weapon?
I can't really say that, though I have some facts that should show which perks should use it.

How do perks affect this gun?
The only two perks that affect this weapon are the Sharpshooter and the Commando.
Sharpshooter gets 50% (on Perk 6) more headshot damage on the plasma projectiles
Commando gets 35% (on Perk 6) faster reload time.

How to carry this weapon the best?
Due to it's heavy weight of 8lbs, most Perks would have to sacrifice their main fire power to carry this weapon. The only perks that should carry this gun are Field Medic, Support Specialist and Commando. The reason: They have light guns or an increased weight limit.

DO NOT FORGET TO USE YOUR OTHER WEAPONS!
I caught myself neglecting the use of other weapon sometimes and many people who use this beauty do the same. As a medic, don't forget about healing at the patriarch fight!

Though I said in the title "The Patriarch", I will go a little into fighting of the other Specimen with this weapon.

Damage Modifiers

• Clots, Gorefasts, Crawler, Stalker and Husks will take 2x damage when in "Stasis*".
  
• Bloats and Sirens will take 1,5x damage.
  
• Scrake and Patriarch will take 1,25x damage.
  
• Fleshpounds will take 0,62x damage.
  Fleshpounds take 1.25x damage while under the effects of stasis, but this stacks with their innate 50% damage resistance to give a final figure of 62.5% (rounded down).

*Stasis:
Stasis is the status Specimen get afflicted by when struck long enough by the Stasis Link (ALT- Fire). In that status, they're slowed, confused, take more damage (explained above) and tend to flail their arms around as if they were on fire. Scrakes can't charge and Fleshpounds can't rage during Stasis. In Stasis, specimen are covered by a white, net-like grid.

The Radar

The radar is a useful thing if used correctly. It works only if the ZED gun is equipped and is permanently online, so you can check the radar while firing. One of it's key features is the *BLIP* noise it will make when a huge specimen comes in range. People said it will also make the noise if there's many small specimen in range, but I couldn't confirm that yet.

Radar Icons

• Small, white dot: Clot, Gorefast, Crawler and Stalker
  
• Yellow head: Husk, Bloat, Siren
  
• Red head: Scrake, Fleshpound, Patriarch (slightly bigger head)

Note: The bigger size is useless as there will be no Scrakes or Fleshpounds at the Patriarch

This gun is a wonderful support weapon. Unfortunately many people forget about the aspect of being able to give your time orders or alerts with the radar. Though people can hear the noise it'll make, too.

Things you should do in a team:

• Stasis Link the big ones, so they'll do a minimum of harm to your teammates (or yourself)
  
• VOICECHAT! Don't stop to type, simply give orders per mic. (Highly recommended to test your microphone quality first.)
  
• Try to coordinate with teammates, the Projectiles and the Stasis Link will get stopped by teammates. Watch out to not fall off somewhere, trying to get a clear shot.
  
• Inform people about the locations like (Red, 20m, stairs). It's far more useful than the *BLIP*
  
• Don't forget the usage of other guns, the primary fire is rather ineffective.
  
• IMPORTANT: Tell your team when you're gonna buy this gun, and don't hesitate to ask for dosh when you don't have enough for the last fight!

Here we are, either Wave 5, 8 or 11.The big one's coming and you got the big ones in your hand.
Not many people decide to grab the ZED gun, but if they know what they're doing they are SIGNIFICANTLY raising your chances.

Given that you're the one that bought this gun, here's some tips how to use it against the Patty.
NOTE: I won't give any basic information about the fight like how to dodge his attacks. Check other guides for that.

He spawned, so you all have a faint clue where he's coming from. But only YOU will know his exact path, so keep the ZED gun on your shoulder and try to aim at the direction the radar is showing. Your team will get alerted by the blip and instinctively check the area you're looking at. If he's getting close, try to shoot him with the "Stasis Link" to make him visible for your teammates. He will catch the beam so there's a forcefield mid-air that makes him visible when he is invisible. Try to Stasis him ASAP in order to maximize the damage.
The stasis will wear off VERY FAST if you don't keep the beam up, so try to keep the pressure up while conserving the mag size as much as you can. It gets depleted in a few seconds when firing a constant Stasis Link.

He flees, what now? There's three cases I decide, but in the end it's up to you.

Case 1: Still under Stasis and your mag's over 40.
Keep him under Stasis and let your team try to kill him, don't forget your Stasis is the key to that kill as you leave him really vulnerable and your teammates quite protected. Reloading is almost a guaranteed failure, so reload only when you're at 0 clip. If he managed to get away, skip to Case 3.

Case 2: No Stasis but almost full clip.
If he was fresh out of Stasis, try to get him back in ASAP and chase him down. If you fail, go to Case 3.
If he was out of stasis for a little while, let him flee and follow Case 3.

Case 3: No stasis, low clip -> LET HIM GO
Running after him would be nothing but splitting up the group. Maybe some will follow you but nobody will guarantee for saftey there. Instead, just wait. Let your mates fend of the Clots while you reload. You NEED to have a full mag when he returns.
If he returns, Stasis him and let the others gun him down, he usually doesn't survive it. If he does, do the case check, though it should be easy to finish him now.

Taken by suggestion from Gab Nuwoll:
Ensure that nobody, either specimen or player is near you when you try to stasis pat. The zed gun has a nasty habit of showing your beam connecting client side but its actually being blocked by something server side. It takes about 35 energy to get him into stasis; so don't let off until he's blue. Once he's in stasis, make sure he stays like that until his death, even if you have to chase him down. After the first try, you may not have another chance to do it.

Keeping him in stasis is as easy as alt firing every 2-3 seconds for a single burst. You can stasis him indefinitely like this and I would suggest you stay medic so you can keep up with him and ensure you survive his attacks while you attempt to stasis him. If you have full ammo on the first attempt, it might not be a bad idea to fire 2 or 3 regular shots between stasis bursts, just make sure a stasis burst burns the remaining ammo. Otherwise the reload might take too long before the stasis burns out.
All credit for that goes to Arblarg

Tips:

• Never get reckless.
  People tend to rush after him carelessly, just to kill him. Most of the times they are the ones that end up dead, so better take your time and let him return to you.
  
• Aim for the head.
  Stasis applies way faster if you "lazer" the head of a specimen. It helps you conserving your ammo and will eventually decide if he dies at the first contact or not.
  
• ♥♥♥♥ primary fire.
  I have seen what it does and I was not amused. You and your clip are better off keeping the Stasis up. (Personal opinion, hang me if you want)

This is it. My first guide here about a weapon I recently started to love.
Remember, when you are using this weapon, YOU ARE SPECIAL!

Feel free to tell me if I made any mistakes or forgot to point something out in the comments.
If you like it or it has been helpful, feel free to leave a rating, and recommend it to others.

And yes, I took some info of the wiki, deal with it.