Specification:
VB-15: Diopter(△):1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30.
HB-16: Diopter(△):1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45.
The warranty time is 18 months.
If you have any question about the prism bar please without desitate to ask us we will do our best to help you to solve.