The cokin 58mm pure harmonie slim uv mc filter has been designed as an everyday clear use filter that reduces bluish casts of daylight while absorbing ultraviolet light the purpose of its ultra thin profile is to ensure it is ideal for use with wide angle lenses and prevents vignetting this uv filter is safe to leave on lenses at all times and can be used as a protector it is able to prevent dust and moisture from reaching your lens element and provide additional protection