This filter is a combination between a Neutral Density Grad 0.6 Hard Edge and a Twilight 2 Grad. The Twilight color graduated filter is graduated from darkish blue at the top to a pink horizon. It provides a cool image ideally suited to creating a late afternoon/early evening twilight effect. The ND Grad portion is primarily used for light reduction in skylines of landscape shots. The hard edge has a more defined hard lined transition and is usually used for longer focal lengths. The 0.6 filter reduces light by 2 stops. Formatt-Hitech filters are made from the highest quality 1.5mm optical resin.