Berg connectors have a 2.54 mm (=.100 inch) pitch, pins are square (0.64 mm x 0.64 mm = approx. 0.025 x 0.025 inch), and usually come as single or double row connectors.
Many types of Berg connectors exist. Some of the more familiar ones used in IBM PC compatibles are:
the 4-pin polarized Berg connectors used to connect 3.5-inch floppy disk drive units to the power supply unit, usually referred to as simply a "floppy power connector", but often also referred to as LP4. This connector has a 2.5 mm pitch (not 2.54)!!