You can also do it with NOT gates. The driver needs to overpower the gates to change the bit and then it acts like a D flip flop rather than an RS flip flop like NAND gates will. But that’s generally how they’re actually made. SRAM generally looks like this: https://upload.wikimedia.org/wikipedia/commons/9/9d/SRAM_Cell_Inverter_Loop.png The side transistors are called access transistors; they’re there so you can selectively read/write, but aren’t needed to store the bit.