Waltham balance staff 28210 8 days 1910 (ht. 600)

Axe de balancier Waltham / 1 Waltham balance staff
28210 8 days (1910)

Some discoloration and sign of age, see pics
Dimensions : height 600 / half-height 344 / balance arbor 123 / hairspring collet 91 / roller 60