This is a 28 pin Narrow type Zif Socket (Zero Insertion Force). This socket works as a test board for IC. The device is incorporated with a lever actuator, which reduces the damage of IC leads during insertion and withdrawal.
The socket uses high quality contact surface or leads plated with gold over nickel. It has standard 2.54mm pin spacing and extra wide contact zone, which allows the insertion in rows from 7.62mm to 15.25mm and makes it a universal socket.