The most important part of the SW150 system is the adaptor ring. This will allow the filter holder to be attached to your lens. Each adaptor ring in the range has a slight design variation, so make sure you purchase the correct version for your lens
In addition to the adaptor ring, you will also require a filter holder. Once the adaptor ring is attached to your lens, the filter holder simply locks on, the filters are slotted in, and your system is ready to use. The filter holder comes assembled with two slots, allowing you to combine filters where necessary.
Once attached, the filter holder can be rotated. This means that filters such as neutral density grads can be used at an angle, for precise control.