The Heliopan 127mm KR 1.5 Skylight (1A) Filter is a general use filter with a slight pink tint to help improve overall color accuracy and clarity. The light pink coloration helps to reduce the overall bluish cast of daylight and is especially effective when photographing landscapes and in shade. It is also useful as a general protective filter to leave on lenses at all times. Filters help to reduce dust and moisture from reaching your lens element and provide additional protection in case of drops or situations where scratching could occur. The front and rear surfaces of the filter both feature a single anti-reflection coating. Each coating helps to increase light transmission by reducing reflections, scattered light, and ghosting. Additionally, they offer protection to the filter substrate while helping to keep the glass clean for longer than uncoated glass. This Heliopan filter is constructed from Schott glass for increased optical clarity and color fidelity. It features a brass filter ring for durability as well as jamming prevention.