The IC 74166 Parallel-Load 8-Bit Shift Register is a parallel-in or serial-in, a serial-out shift register with 77 equivalent gates, gated clock inputs, and an overriding clear input with a complexity of 77 equivalent gates. The shift/load input determines whether the mode is parallel or serial. It can operate in a variety of working voltages and environments. It also works with CMOS, NMOS, and TTL directly.

The IC’s output is always in TTL, making it simple to interface with other TTL devices and microcontrollers. Furthermore, the IC 74166 is smaller in size and has a significantly faster speed, making it highly reliable on any device.