Accurate Surgical new instrument. 

Oval Areola Marker

Watch the demonstration video by Dr. Larson on the ASSI YouTube channel linked here:

References: Annals of Plastic Surgery Anatomical Parameters for Nipple and Areola Diameter in Males (PDF)

Journal of Aesthetic Surgery, Defining Normal Parameters for the Male Nipple Areola Complex: A Prospective Observational Study and Recommendations for Placement on the Chest Wall (PDF)