Environmental Protection Upgrades
Source Player Core pg. 268
You can personalize armor by purchasing and installing armor upgrades. Armor upgrades are installed into the upgrade slots of armor; one armor upgrade occupies one armor upgrade slot. The number of upgrade slots a specific suit of armor has is noted under that armor's description. You can install an armor upgrade with the Install Upgrade activity, which takes 10 minutes to perform. Unlike many other types of equipment, armor upgrades run on kinetic energy created by your body's motion, and they don't need external batteries. They function only when installed in armor you're wearing properly.