Abstract: A connector for a circuit component comprises a rigid support frame having a central aperture into which the component may be placed, and spring means around the support and having a plurality of spring projections which project beyond the support frame for co-operation with perforations in a planar substrate, such as a PCB. The projections may have hook-shaped lower ends which locate against the underside of the PCB. A layer of anisotropically electrically conductive material is located between the component and the substrate. The connector and component together with the conductive layer in position form a substrate-mountable device.