What kind of filters do I have?

[Rigby470]

I am selling off some of my old gear that I no longer use. I ran across a couple of filters, and I'm not sure how I should list them for sale. . .or how much to charge for them.

The markings on the filters/cases read:

1. B&W 72 Farbverlauf Grau 50%. (There is a gray shadow extending about halfway across this filter)

2. Hoya 72 Multi-coated Slim Ultra ND4X.

Thanks in advance for your help.

[That_Fox]

The first one sounds like a graduated neutral density filter and the second one is a neutral density filter.