Other companies case gauges are only the length of the case, and often have a step on the end to indicate trim length. Our ammunition gauge and slotted ammunition gauge are the full cartridge length (COL), so they can not have a step on the end of the gauge to show trim length.
On most pistol cartridges where the case headspaces directly on the mouth, the need to trim will be indicated by the headspace measurement. Our gauge will show this clearly.
On rifle cartridges, where the cartridge headspaces on the shoulder or a belt(for belted magnums), there should be some space between the mouth of the case and the corresponding end of the chamber. So you can not use the gauge to check for the trim length. This can be checked with calipers.