The Spiked Armor can be found in Sword Coast Adventurer’s Guide, page 121.
You have a +1 bonus to AC while wearing this armor.
Spiked armor is a rare type of medium armor made by dwarves. It consists of a leather coat and leggings covered with spikes that are usually made of metal.
The wearer has Disadvantage on Dexterity (Stealth) checks.