Methods and devices for interconnection of Printed Circuit Boards (PCB) and to one another or to other components using ultra low profile electrical connectors. Examples include male and female inserts for placement in the plane of a PCB, and PCB assemblies comprising one or the other of male or female inserts for such placement. Further examples include surface mounted male and female connectors and PCB assemblies, in which the connectors comprise base members and connector elements configured to couple to corresponding assemblies on other PCT assemblies by movement in a horizontal plane relative to the PCB.