Loose Ceramic Balls 5/16"=7.938MM ZrO2 (zirconium Oxide), this is a popular size that could be used in any application that uses this size 5/16",Ball is made of Ceramic ZrO2 . ProductSiteLaunchDate : 2024-08-07T08:28:31.609Z Size : One Size Style : Diameter UnitCount : 1 UnspscCode : 31170000