If Exists allows a designer to check a specified Record Type and Property combination for a specific value. Based on a True or False result assign an action chain to execute in a view.
In the example below we've stored the Inventory ID in a variable to ensure it doesn't exist in the Record Type before executing the Save action. If the ID does exist a Show Message action will notify the user of the duplicate entry and not save any dirty records.
To check a property for a selected record, as opposed to the entire Record Type, store it as a variable in the action chain.