Specifies the output mass range (Da) of the zero-charge deconvoluted mass spectrum. If either field is left blank and target masses have been defined, the output mass range will be set to a +/- 25% range around the minimum and maximum target masses. With the Use 0.1 Da Mass Step Size option checked, ProMass will plot output data in the deconvoluted spectrum at 0.1 Da intervals. If this option is unchecked, 1 Da intervals are used. The 0.1 Da step size should be used whenever the peaks in the output spectrum are expected to be narrow, e.g., peptides and other molecules under 5 kDa.