The RUST Road Sign Kilt is a partial leg covering with its earliest concept art dating back to June 2015 and the most recent art iteration releasing May 2017. Originally called road sign pants, Facepunch later changed the name to reflect the kilt quality. In order of protection and excluding the heavy metal set, the road sign kilt is the best available in-game leg armor type for lower body projectile protection.
It operates much in the same way that Wood Armor Pants do. The projectile protections of the road sign kilt far outweigh those of the wood armor pants, but many Winter biome players prefer the wood armor over the metal because of the cold protection difference.
They are found in mid to high-tier loot crates and boxes and drops from multiple types of scientists. Players can research it at a research table or through scrap investment at a Tier 2 Work Bench.