The 4027 is a dual in-line JK flip flop IC. Meaning it has two JK flip flops inside it and each can be used individually based on our application. The term JK flip flop comes after its inventor Jack Kilby. The JK flip flops are considered to be the most efficient flip-flop and can be used for certain applications on its own. The flip-flops are also called as latching devices meaning it can remember one single bit of data and latch the output based on it, due to this property they are commonly used as shift registers, control registers, storage registers or where ever a small memory is required.