Product review (5 stars): This is an OEM part = Frigidaire 5309957097
(from info with new switches, this appears to be a possible replacement
for an 8" element  - AND also some 6" elements)

Purchased this switch - with all indications that it was correct
for our 1964 Frigidaire Flair Custom Deluxe RCIB 645-2.
(when RCIB 654-2 is added to - 'Enter your model # to make sure this fits'
It's validated that it does. = BUT it didn't.
(needed a switch for an 8" infinite heat element and heat-minder element)

After much research and receiving the switch that IS correct =
wanted to mention that the paper that comes with these Frigidaire switches
contain info for multiple switches.
>>> The information given there, about this switch = follows.

>>> "Kit No 9957097 (same as 5309957097 - they updated the model #)
contains switch part 9950917 and replaces (among others)
part numbers - 7521247 - 7531784 - 7531785 - 8004948 -
6564838 'OLD' heat-minder switch > (our 'heat-minder' element was 8" element)
and some speed-heat switches" > (our 'speed-heat' element was 6" element)
>>> Sorta confusing - BUT I'm guessing the KEY WORD IS 'OLD' heat-minder switch.
(apparently there's at least two heat-minder switches)

The switch that did fit our 1964 Frigidaire Flair Custom Deluxe RCIB 645-2 is
>>> "Kit No 9957099 (same as 5309957099 - they updated the model #)
contains switch part 9950919 and replaces
part numbers - 7521243 - 7521245 - 7521370 - 7522792 - 7525721 - 7525722 -
7526396 - 6539547 - 6563695 heat-minder switch"
(which was apparently the version of heat-minder switch of our model)