Loose 9/32" inch Tungsten Carbide Ball Bearings 9/32" inch = .281" inch G25 One Loose Balls One Loose 9/32" inch Tungsten Carbide Ball Bearings Balls are made of tungsten carbide Balls size is 9/32" inch 7.144mm Grade is G25 And it meets grade 25 sphere tolerancem Loose Ball is extremely hard alloy made from tungsten and carbon And it is high corrosion wear resistance.