Abstract: A gripper head (18) for use, for example, with a pick and place robot (2) comprises a body (26) comprising a pair of housings (28) each containing a pneumatic piston and cylinder unit (62) and being connected together by means of a slide plate (30). The piston and cylinder units (62) are arranged in opposed relationship on opposite sides of a central vertical axis (Z) of the body (26). The slide plate (30) defines in cooperation with a top cover (32) a slideway (48) receiving slides (82) from which depend side plates (76) connected to gripper jaws (98). The slides (82) are positively connected by a link (92) which is pivotable about a pin (88) coincident with the central axis (Z). Pins (96) on the link (92) engage in transverse slots (86) in the slides (82) to ensure that the jaws (98) are moved by piston rods (66) of the piston and cylinder units (62), always simultaneously and by the same distance, between an open position to receive an electrical connector (C') and a closed position to grip it.