The HP-10B is a student business calculator. The older model of this calculator proved to compete well with the higher end RPN HP-12C. The later-model HP-10B II is essentially a cosmetic upgrade offering the same overall functionality but actually reduces the available numbered-storage registers from 15 to 10. Early production runs suffered from poor quality; newer calculators have apparently solved this shortcoming. Two versions of the 10B were produced, one with green lettering around the keys, one with orange. The functionality of the two versions appears to be identical.