Why is the RH response time less for the HOBO MX2301 vs the HOBO MX2302?

The RH response time in the HOBO MX2301 internal logger is faster than in the HOBO MX2302 external logger. This is due to the geometry of the location of the internal sensor in the loggers. In the MX2301 logger, the RH sensor is located directly behind the vent. The MX2302 logger sensor is covered with a cap and membrane, thus giving it a longer RH response time.

More information can be found in the MX2300 manual:
MX2300 Manual

Associated Products: 
Measurement and accuracy