Dual J-K Master-Slave Flip-Flop - CD4027
CD4027B is a single monolithic chip integrated circuit containing two identical complementary-symmetry J-K master-slave flip-flops. Each flip-flop has provisions for individual J, K, Set, Reset, and Clock input signals. Buffered Q and Q\ signals are provided as outputs. This input-ouput arrangement provides for compatible operation with the RCA-CD4013B dual D-type flip-flop.
The CD4027B is useful in performing control, register, and toggle functions. Logic levels present at the J and K inputs along with internal self-steering control the state of each flip-flop; changes in the flip-flop state are synchronous with the positive-going transition of the clock pulse. Set and reset functions are independent of the clock and are initiated when a high level signal is present at either the Set or Reset input.
Description above from Texas Instruments, see product information for more - http://www.ti.com/product/CD4027B