The E-Tech guns have a special, unique barrel and glow. Their attacks vary too from lasers to plasma / energy balls that are slow. The color type on these for the label rare scale is Magenta.
E-Tech Gun Names
There are special names for E-Tech guns that pertains to the type of gun it is. This is NOT the full name list -- and please note that the names listed here have even more variations than seen (which varies even more depending on how rare the E-Tech gun is).
Assault Rifles: BIASSter, Blaster
Pistols: Dart, Dubble Spiker
Rocket Launchers: Launcher, PBFG, PRAZMA CANON, Topneaa
Shotgun: Blashter, Splatgun
Submachine Gun (SMG): Plasma Caster
Sniper Rifle: Hybridfication, Moloko, Railer
How to Get E-Tech Weapons
You can find these weapons in many ways.
-- You can get an E-Tech weapon from Dr. Zed's quest / mission: "Medical Mystery" from killing Doc Mercy
-- Using gold keys, you can get E-Tech weapons -- so if you have a lot of keys, then you can farm E-Tech weapons (check Borderlands 2: How to get All Golden Keys (Cheat)) for good loot / treasure
-- Bosses can drop E-Tech guns so farm them! Check out Borderlands 2: How to Kill Terramorphous the Invincible AND also check Borderlands 2: Vermivorous The Invincible - harder than Terramorphous the Invincible for two good bosses to kill for amazing E-Tech loot, though you can actually fight ANY boss.
-- You can find E-Tech in standard treasure chests sometimes
-- Normal enemies sometimes drop E-Tech too
Best E-Tech Weapon
It's hard to choose what the best Eridium Tech Gun is.
And unfortunately, there is no E-Tech gun that is specifically better than the rest.
The Predacious PBFG is extremely powerful. Yet depending on your luck, you can find one hell of a shotgun too (such as the E-Tech Basic Splatgun).
Borderlands 2 E-Tech FAQ
Here's a little question and answer section for you guys for the more specific information you may be wondering about.
Q: Do I have to kill a special enemy to get E-Tech gear?
A: No. You can fight ANY enemy (mostly) and you will have a chance to find an E-Tech weapon. However, the harder the enemy, the higher the chance -- and thus bosses are recommended.
Q: Are E-Tech weapons rarer than Legendary weapons?
A: Legendary weapons CAN be E-Tech so it has no baring. However, Legendary weapons are more rare than just E-Tech weapons.
Q: Are E-Tech weapons stronger or better than rare, epic, or legendary weapons?
A: Usually -- no. A lot of E-Tech weapons aren't as strong as their counterparts -- but that's not always the case. You CAN find E-Tech weapons that are stronger.
Q: Are there E-Tech - Seraph guns?
A: As far as we are aware -- no.