The Vault “Hybrid Lubricating System” made by Unique Functional Products is the best new product on the market for wheel bearings on boat trailers.  Typically there have been two types of lubricants used for wheel bearings, grease and oil.  Each type of lubricant has their advantages and disadvantages.  Typically on greased bearing units the bearings would run very hot and there was wear on the bearings due to friction.  On oil bearing units they would leak causing the consumer to constantly have to inspect and do maintenance on them. The Vault uses semi-fluid oil in a pressurized chamber to protect as well as lubricate the bearings, requiring no inspection, no maintenance, and no service.  At lower temperatures the oil is thick but as temperatures rise during towing, the Vault’s hybrid oil thins, replenishing the bearings with lubricant and dissipating heat.  The Vault comes with a 5 year, unlimited mile warranty and an extended 5 year warranty can be purchased for very little cost.  The pressurized chamber means nothing gets in or out.  Hybrid oil constantly replenishes the lubricant to the bearings, this allows the bearings to run cooler due to reduced friction.