Max Size is the maximum size that the sizing controls will return to the mesher. This option is available when Use Adaptive Sizing is set to No. Specify a value greater than 0 or accept the default.
Note:
The Max Size option is hidden if there are no solids in your model.
For information about overriding sizes, refer to Overriding Sizing Minimum and Maximum Sizes.
For information about the relationship between the Element Size control and the Min Size, and Max Size controls, refer to Understanding the Influence of the Sizing Options.