Thickener—Added for a more solid consistency, thickener also increases the heat and moisture resistance of grease. Choose grease with a thickener that’s best for your application. Lithium is a general purpose thickener. Calcium sulfonate and aluminum resist oxidation, which keeps the grease from hardening when it’s exposed to air for long periods. Calcium sulfonate resists higher heat than aluminum. Silica withstands the widest range of temperatures.

NLGI Consistency Grade—The higher the grade, the thicker the grease. Lower grades are best for cold temperatures and lubrication systems where grease needs to flow. Grade 0 is about the consistency of mustard. Grade 1 feels similar to tomato paste. Grade 2 is about as thick as peanut butter.

Base Oil—The foundation of a grease. Mineral oil is more economical, but synthetic oil lasts longer and performs better at extreme temperatures.

Melting Temperature—When grease melts, it runs out of equipment and leaves it dry. Once melted, it won’t regain its original consistency. Choose a grease with a melting temperature that’s higher than your maximum operating temperature.