This article is considered accurate for the current version (0.46) of the game.
Refined Materials, often referred to as "rmats" (ɑr-mæts), are a building resource of Foxhole. They are an advanced resource which is harder to come by than their more common counterpart, Basic Materials. They're used in crafting higher tier Vehicles and Weapons.
Refined Materials are created in the Refinery by processing Components. Just like sulfur, the materials are processed in a 20:1 ratio.
Refining 100 Components takes 5 minutes for 5 Refined Materials