Benro FH100M2 filter holder

Polariser

The polariser can be easily rotated from behind the camera using a knurled ring, but there’s no way of fixing it in one position.

Geared adjustment

Rotating this knob precisely adjusts the position of graduated filters. It clicks into three positions, one for each filter slot.

Mounting clip

This sprung, sliding red tab is used for clipping the filter holder onto the lens adapter ring. Rotating the small blue knob locks it into place.

While there's any number of filter holders available for photographers who wish to exploit polarising, neutral density and graduated filters to enhance their images, most essentially work to the same