Reading dimension in datasheet
Physical dimensions inches (millimeters) unless otherwise noted.


The dimensions are given in inches and between parentheses the same is shown but in millimeters.

So the top right measurements say:


0.335 ... 0.344 inches (minimum ... maximum)


or


8.509 ... 8.738 millimeters


When designing a PCB you want to reserve at least 0.344" for it or it may not fit. The total length varies somewhere between the given minimum and maximum values.