Yes and no - Yes to the circular one on the back: it is interchangeable with most standard sized ball markers (diameter of 25mm). No - the alignment aid ball marker on the front of Gannet™ is unique to Gannet™. At the moment no other ball markers fit nicely in its place. We will be launching other designs which can be purchased at a later date. Please sign up to our newsletter to keep updated with any new ball marker launches.