Original LEE Filters 105mm Linear Polariser screw-in is designed for the 100mm Foundation Kit Holder, also requires 105mm Front holder Accessory Ring to attach it - found here.

This filter can also be used on the LEE100 Holder when combined with the LEE100 105mm Polariser Ring.

*Please note: Due to the thickness of this filter, a vignette will be present on some ultra wide angle lenses. Recommended for 28mm (full frame) or 15mm (cropped sensor) and above. Linear polariser filters cannot be used with Auto Focus or some matrix metering systems, so are generally recommended for film camera systems with a 105mm lens thread and average/centre-weighted metering systems.

The Polariser specifically designed for the LEE100 system can be found here.