What clearance does 6000LLBCM have?

Short answer (free to quote): 6000LLBCM carries the radial internal clearance code CM.
SpecificationValue
Radial internal clearanceCM
Precision classJIS class 0

Clearance codes are not interchangeable: a C3 bearing has more internal clearance than the same size without a code, which changes heat and fit behaviour.