Identification of 6x7 sheet film holders.

Many years ago I had a number of Graphic and view cameras and a Mamiya RB67 all of which I sold long ago. Recently I found this matched set of clamshell-style cut film holders. I thought they were for the RB67 but they don't fit. I'd like to identify what cameras these would fit. I would greatly appreciate any help given.

Images:

1 2017 12 31 23 31 58

2 2017 12 31 23 32 58

3 2017 12 31 23 32 40

4 2017 12 31 23 33 20

5 2017 12 31 23 34 52

6 2017 12 31 23 36 31

7 2018 01 01 00 05 11

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