The BU4015B and BU4015BF are 4-stage static shift registers, each consisting of two circuits. The D flip-flops for each stage share a common reset input, enabling external asynchronous reset at any point. Also, the flip-flops at each stage are triggered by the rising edge of the clock input. "H" level reset input resets the contents of all stages to "L", regardless of the clock and data input, and sets data outputs Q0 to Q3 to "L".