ZIF stands for Zero Insertion Force. ZIF sockets are commonly used in ECUs where the EEPROM will be removed and reinserted frequently.

"ZIFing an ECU" is when you desolder the stock EEPROM and solder a ZIF socket in its place. Ensure that you choose a ZIF socket that has the same number of pins as your EEPROM. Keep in mind that some ZIF sockets are physically larger then regular IC sockets. If the IC you want to add a ZIF socket to has many parts right next to it, it may not fit. Double-check before ordering...

36-pin:

28-pin: (digikey part # A347-ND, Future Active carries them much cheaper for tubes)