Lee 105mm rotating polarisers are attached to the filter system via a special ring (sold separately) that is fitted to the front of the holder (sold separately). This allows the polariser to be rotated independently of any grads used & is ideal for landscape photography where extra flexibility is required. These high quality glass filters manage the waveforms of light travelling to the camera from most reflective surfaces. Glare & reflected light can be altered by rotation of the polarising filter. The effect can be seen through the lens of reflex cameras as the filter is rotated. When used outside on sunny days, polarising filters have the effect of saturating colours & deepening blue skies. They can also be used in conjunction with other filters (although the polariser should always be placed in front of polyester filters to ensure it functions correctly).