There is a lot of armor to unlock in Halo 4. Most of the Halo 4 armor sets don’t include armor for Forearms, so you have to unlock them separately.
Here is the list I have compiled of all the forearm armor I’ve seen in all of the dev videos. I think I have them all, but let me know in the comments if you find anything that’s missing.
Check out my other articles if you’re looking for the unlockable armor sets or unlockable leg armor.
Unlockable Forearm Armor
All of these can be unlocked naturally in the game.
Contoured – Reach rank SR-39
Contoured CHVR – Unlocked with the commendation Perfection – Master
GV-09 Locking – Reach rank SR-22
Inner-plated – Reach rank SR-30
Mark VI – Complete the Campaign on Legendary difficulty (solo or co-op)
Outer-plated – Reach rank SR-34
Twin-plated – Reach rank SR-9
Twin-plated AEON – Unlocked with the commendation Close Quarters – Master
XV-27 Shifting – Reach rank SR-48
Exclusive Forearm Armor
Here is the list of forearm armor that is only available from pre-orders, collectors editions, or console bundles.
Fotus – Included with Halo 4 console bundle
GV-09 Locking FRST – Pre-order bonus Gamestop
Inner-plated WEB – Pre-order bonus from Amazon
Outer-plated RPTR – Pre-order bonus from Best Buy
Recruit PRME – Included in the Collectors Edition of Halo 4
XV-27 Shifting CRCT – Pre-order bonus from Walmart
XV-27 Shifting PULS – Pre-order bonus from the Microsoft Store