This board is intended to provide strain-relief when connecting an adapter cable to the pin headers on a CP2102N board from adafruit (https://www.adafruit.com/product/5335) . The slots are intended for zipties, or similar. I probably should have silkscreened on the rx, tx and ground and maybe rounded the corners. The CP2012N board is marked, so matching pins up is not too challenging. The primary motivation was to attach a 3.5mm headphone plug. I am using 8-pin 0.1-inch sockets (e.g. https://www.mouser.com/datasheet/2/418/7/ENG_CD_215297_E-2028197.pdf … more expensive than the board!).