The difference between the HAKKO 441 and 441B Footwear Testers is the threshold for high resistance levels.
The old 441 had a high reading of 1x108while the 441B has a selector switch to choose this level or the 1x109 level whichis part of the JIS T 8103 standard for antistatic footwear. In the standard, the ambient temperature affects the value that is considered high resistance. At 23°C the limit is 1x108 but at 0°C the limit is 1x109. All measurement limits in the standard are based on a 50% RH.