Most equipment slots accept any type of Mod. However, some slots are "polarized" with an innate Polarity. Each type of Polarity has a unique symbol. Polarities include:
Madurai - V (Damage, Powers) - Commonly dropped by Grineer.
Vazarin - D (Defensive, Health, Armor) - Dropped by all factions.
Naramon - Dash/Bar (Utility, Misc.) - Commonly dropped by Corpus.
Zenurik - Scratch - Introduced in Update 13.0 (2014-04-09) and mainly used for Warframe Augment Mods, in addition to some Melee Stance Mods.
Unairu - R - Introduced in Update 13.0 (2014-04-09) and used for certain Melee Stance Mods.
Penjaga - Y (Companion Abilities) - Dropped by all factions.
Umbra - U (Anti-Sentient Mods) - Obtained upon completion of The Sacrifice.
Any - O (Universal polarity) - Can be only applied by 
Aura Forma and 
Stance Forma on the Aura and Stance slot respectively.
A mod's polarity type is noted in the top right corner of its card, next to the drain cost. When a mod is placed into a matching polarity slot, the cost of installing the mod will be reduced by 50%, rounding up to the nearest whole number. In contrast, placing a mod in a slot with a different polarity will increase its cost by 25%. Again, this cost is rounded to the closest integer.
For Aura and Stance mods, polarities increase or decrease the amount of bonus mod capacity that the mod instead provides: matching polarities will double it, or increase the bonus mod points by 100%; while non-matching polarities reduce it by 20%.
A certain polarity layout will make certain mod builds more efficient. Naturally, Warframes and weapons will start with varying polarity layouts (or none at all), that differ from the natural polarity slots of other pieces of equipment. These starting layouts will make it easier to use the weapon and have the most effect the first time the equipment is ranked up. Later, however, polarities may be added or changed by the use of 
Forma.
Polarization[]
- Main article: Polarization
Players may use Forma, a rare item obtainable from Void Fissure missions or the Market, to add or change a polarity on a piece of equipment that has attained rank 30. This increases the weapon or frame's overall strength by increasing the possible mod combinations that may be placed on it. Using Forma to add/change a polarity slot will reset the equipment's rank to zero, requiring the equipment to be leveled up again. Additionally, polarization allows players to rearrange polarity slots as they see fit, including polarities that were built into the equipment to begin with. As of Update 15.1 (2014-11-05), the aura slot's polarity cannot be swapped with another slot's.
Currently, there appears to be no cap on the number of times a weapon may be 'polarized' or what polarizations are possible (on a weapon with eight blank slots, you could polarize it eight times with the same polarity if you so wish) though good judgment on how you wish to build a weapon undoubtedly means variety will serve most if not all Tenno well.
Innately Polarized Weapons[]
Trivia[]
- It is apparent to those who know the Orokin Script that some Polarities are in fact the same symbols as some numbers and vowels, either rotated or flipped:
- Madurai () is the numeral 4, or an upside-down 2.
- Vazarin () is the numeral 5 flipped vertically or an upside-down 3.
- Naramon () is similar to the symbol for 1, rotated 90° counter-clockwise.
- Zenurik () is the vowel "I" (as in the word "Pit") rotated 90° counter-clockwise.
- Penjaga () forms the number 10.
- Penjaga is Indonesian/Malay for "guardian" or "protector", and mods in this category are reserved for Companions.
- This can also be interpreted as I/O, for the fact that this polarity is only present on mods that influence companion behavior.
- Unairu () does not have a perfect connection to the Orokin Script, though Unairu is perhaps similar to the shape of the vowel "AYE" (as in the word "Price").
- Madurai (
Dante,
Jade, 
Protea, and
Protea Prime are the only Warframes with an innate Universal aura polarity.- According to Devstream 55, the names of the polarities correspond to old Tenno schools. These names are also used for the clusters depicted in the Star Chart 3.0 prototype also featured in the same Devstream.
- Up until Update: The Silver Grove (2016-08-19), there was also a Koneksi (
) polarity that was reserved for 
Fusion Cores, which have since been replaced by Endo.
- In line with the naming schemes used by the other polarities, Koneksi does not have a perfect connection to Orokin Script, but it does bear similarities to the vowel "OH" (as in the word "Goat").
- Similar to Penjaga, Koneksi is also Indonesian/Malay in origin, in this case translating to "connection", reflecting how Fusion Cores were the only mods that bore this Polarity.
- As of Hotfix 36.0.6, There are...
- 449 Madurai mods.
- 335 Naramon mods.
- 182 Vazarin mods.
- 8 Unairu mods.
- 209 Zenurik mods.
- 88 Penjaga mods.
- 5 Umbra mods.
- 75 mods with no polarity.
- 449
Patch History[]
Update 8.0 (2013-05-23) POLARIZE WEAPON SYSTEM!
- Got your gear to level 30? Prepare to Polarize!
- With the newly discovered “Forma”, you can now add or swap a Polarity value on your gear every time you reach level 30.
- Forma can be purchased or found through Daily Login Rewards, Alerts, or possible Missions rewards for completing missions in The Orokin Void.
Update 7.0 (2013-03-18)
- Introduced.
