Russian Volume Lashes (2D, 2.5D, 3D, 3.5D, 4D or 4.5D) are ultra fine synthetic lashes that are fanned, staggered and stacked onto each natural lash. However, as they are much thinner and softer so your lash technician is able to apply more than one to each natural lash typically applied in a fan-like shape, which adds to the ‘volume’ look.