The magnetic Master Kit from Kase starts with the included threaded adapter ring, which will allow you to use the magnetic circular filter holder. The Master Kit includes both a magnetic 10-stop ND filter and a magnetic Circular Polarizer that can be attached to the filter holder, as well as a 95mm Soft Grad ND 0.9 filter that can be freely adjusted to help line up the graduation line in your image.
The Master Kit ships in a leatherette storage case and includes a 95mm magnetic front lens cap.