The 74HC595 is a commonly used general purpose shift register available in DIP16, SSOP16 / TSSOP16, and QFN packages. A shift register is composed of one or more latch circuit called stages which when fed data input, move their current contents to the next register in line and accept the new data. Repeating this 8 times fills the 8-bit register with a byte of information (8 bits) allowing for a parallel output on pins Q0 -Q7. In microcontrollers where space, and consequently pins, are limited, a shift register, such as the 74HC595 can be used to allow just a few pins of the microcontroller to control a larger (possibly much larger) amount of lines (such as 8 LEDs) in the picture above. Additionally shift registers can be used as buffers for fast transmission between circuits when reception time is brief and periodic, such as in the transfer stream of a sound playback device with serial I/O FLASH memory. The shift register can buffer, to an extent, the data (composed of bits) and dump the contents rapidly to the control processor in a single clock cycle.