We've searched for FPC cables connectors before on the Great Search (https://blog.adafruit.com/2020/08/02/desk-of-ladyada-when-searching-for-fpc-connectors-its-good-to-be-flexible-adafruit-digikey-deskofladyada-thegreatsearch/) but this time we're going to try to find a specific size: we need a 18-pin 0.5mm pitch bottom-contact connector for use with our EYESPI cables and boards (https://www.adafruit.com/?q=eyespi&sort=BestMatch) but we don't want it to be too wide!
Most are 13.4mm wide, which is 0.525" wide, and we want it to be no more than 0.5"! Let's look for a slimmer cable connector that will fit on the PCB at 0.45" or less - but still fit all our specifications.
See the chosen chip on Digi-Key at https://www.digikey.com/short/fptn3hh3