A timing aid used to communicate to your dog the exact moment they have made a mistake in training, and that their opportunity to earn a reward has been delayed.

NRMs are most useful for clear, well-defined mistakes that sharply contrast the goal behavior (such as breaking a stay). They are not useful for vague or ambiguous mistakes (such as shaping a dog toward jumping through a hoop).

NRMs are typically a short, neutral word such as "Oops," "Whoopsie," or "Try Again." It is best to say the marker in a calm, neutral, or friendly tone. Avoid using "No!" or anything that sounds threatening. The goal is to give clear information, not to scare or punish your dog.