In events where racers have their own permanent race numbers such as Motocross or cycling, it is critical to capture that number at registration time. One of the key requirements of that field though is that it be unique and no two racers can have the same Racer Number in the timing system. The preset field “Racer Number” accomplishes this by ensuring that when participants register online, it does not allow duplicate numbers to be entered.
To add the field to your registration, click Edit Form.

Choose Add a Form Element

From the Race Fields section, select Racer Number.

Customize the field as needed and click Save.

On the public side of the registration, when a registrant enters a racer number in this preset field and clicks onto the next field, it checks the number in real time against all the other entries and displays the warning following warning if a conflict is found: “Racer number X is already taken.”

Note that you can only have one Racer Number field per registration.
Also note that if your event allows duplicate racer numbers in different classes or events, then this special field should not be uses and you should just use a regular text field to collect racers numbers.