Hinderer factory replacement part. This replaces the factory titanium liner that is beneath the G-10 scale. For 3.5" XM-18, 3.5" XM-18 Skinny, and 3.5" XM-18 fatty only.
Since these are made out of copper they will patina over time, and may ship with some patina on them.
NOTE: Hinderer warns against using these with bearings if your knife has them. The material is softer, and the bearings will wear a track into the liner. Phosphor Bronze or Teflon washers are the only two systems that are factory recommended.