The divine twins corresponding to the Greek Dioskouroi (Kastor and Polydeuces) and the Roman Castor and Pollux, also known as the Tinas Cliniar. This pair is very frequently incised on Etruscan mirrors, facilitated artistically by the symmetry of twins, but also because of their popularity for votive offerings. They also a have liminal character between the mortal and the divine, slipping between the living and the dead. A further association of the twins is with athletics, because of their prowess in horsemanship and associated military activity (Castur) and boxing (Pultuce).
Historical Dictionary of the Etruscans. Simon K. F. Stoddart.