 Until recently, all these names referred to instruments operating up to about 100 Pa and with BSE detectors only.Lately, the Zeiss-SMT VP-SEM has been extended to higher pressure together with a gaseous ionization or gaseous scintillation as the SE mechanism for image formation.Therefore, it is improper to identify the term ESEM with one only brand of commercial instrument in juxtaposition to other competing commercial (or laboratory) brands with different names, as some confusion may arise from past use of trademarks.