Silver-Lube® Bearing Inserts Have Martensitic Stainless Steel Rings and Balls, and Austenitic Stainless Steel Ball Cage, Flingers and Set Screws, in Addition to Durable and Heat-Resistant Silicone Rubber Seals the Grease in this Product is an Aluminium Complex Food Grade Grease, Classified to NSF Grade H1. In the Event of Relubricating Being Necessary, this Type of Grease is the First Choice Replacement.