Hasselblad: Cokin plate filters holder, help?

Hello guys, I received as a gift from an old photographer a Cokin plate (or gelatin?) filters holder that has been used on a Hasselblad. In these pictures you can see what I have.

Do you know how can I use that on my Hasselblad? Which filters does it need?
Thanks you all in advance.

https://www.cokin-filters.com/creative/rings/

A three part system: Adapter to fit lens, filter holder, filter.
Your adapter looks like the universal P499/P486 but seems to be missing the screws to attach to the lens.
Lots of filters and bits on the auction site.

Chris Livsey said:

https://www.cokin-filters.com/creative/rings/

A three part system: Adapter to fit lens, filter holder, filter.
Your adapter looks like the universal P499/P486 but seems to be missing the screws to attach to the lens.
Lots of filters and bits on the auction site.

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Thank you, Chris, as always clear and kind.
For now I'll buy a Cokin P ∅52 ring and I'll use it on a b50-52 adapter ring, that's the best deal.
I'd like to experiment with filters, that's an unknown world for me and sometimes I feel like I want something more from my negatives.
As I saw I guess those filters are still widely available, right?
Thanks again
Francesco

Pleasure, just like the Koala Brothers - "We're Here To Help"

Neutral grads if shooting colour will make the biggest difference, if shooting landscape type stuff, obviously yellow etc in B/W, just not super easy with that set up hand held I found, I have used the Pro-Hood which takes the "sheet" filters.

Chris Livsey said:

View attachment 180037

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Ahahahah that's true!
You know, I'm sure it won't be that comfortable to use, but it will be so for my wallet. A complete set of b50 filters probably will cost me as much as a three lenses set, I don't know if someone made unofficial filters for that mount but I know for sure that the official ones are super expensive. I mainly work on tripods so it won't be that bad.