Loose 1" inch Tungsten Carbide Ball Bearings 1" inch = 1.00" inch G25 One Loose Balls One Loose 1" inch Tungsten Carbide Ball Bearings Balls are made of tungsten carbide Balls size is 1" inch 25.4mm 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.