The first letter after the type code is the tolerance grade:
- Max 0.1%, 100 ppm/°C – A Grade
- Max 0.2%, 100 ppm/°C – B Grade
- Max 0.5%, 100 ppm/°C – C Grade
- Max 1.0%, 150 ppm/°C – D Grade
Datasheet mentions an E Grade too (2.0%) but not sure if that’s still produced.