NLGI licenses certification marks for use on labels of products that satisfy performance criteria and pass laboratory evaluations managed by NLGI. In 1989, GC/LB Certification Marks were designed and standardized by NLGI and ASTM (D4950) to meet requirements for lubrication of automotive wheel bearings and chasses and then written into many original equipment manufacturer (OEM) specifications. Chassis lubricants are designated L, and wheel bearing lubricants are designated G. There are two performance classifications for chassis greases (LA and LB), and three for wheel bearing greases (GA, GB, and GC). The automotive industry is in general agreement that the highest performance classifications (LB and GC) are suitable for service relubrication of vehicles. In 2020, NLGI introduced the HPM (High Performance Multiuse) Certification Marks. In addition to the general HPM Certification Mark, there are additional specifications and Marks for lubricating greases with enhanced water resistance (WR), corrosion resistance (CR), load carrying ability (HL), and low temperature performance (LT).
