Switch between the 2, 3, 4, 6, 10 and 15 stop filters, or if you prefer adjust the setting to show the ND values (0.6, 0.9, 1.2, 1.8, 3.0 and 4.5 ND). You can also combine two ProGlass filters for even more exposure flexibility. The app is designed for fluid and precise operation in the field, with a full range of shutter speeds in 1/3 stop increments and all the controls right under your thumb.