A ZIF (Zero Insertion Force Socket) allows you to insert and remove chips easily from an existing circuits. These are often used for chip programmers or when you need to test a chip without damaging it. Move the lever up and chips drop right in. Move the lever down to 'latch' the chip in place.
This socket is designed for DIP chips of up to 28 pins and 0.3" wide. What's nice about it is it can snap into an existing circuit board or socket that is designed for the chip so you may not have to redesign the board! For example, we snapped it into an Arduino socket, which would allow you to change chips out (if you wanted to put a shield on top, you'll need to fit a set of stacking headers on)