 In many applications this presents no problem, but with those ones requiring uninterrupted 100% relative humidity, it has been found that the removal of ambient gas is accompanied by lowering the relative humidity below the 100% level during specimen transfer.This clearly defeats the very purpose of ESEM for this class of applications.However, such a problem does not arise with the original prototype ESEM using an intermediate specimen transfer chamber, so that the main chamber is always maintained at 100% relative humidity without interruption during a study.