SMD contact springs are available in different sizes and designs and, depending on the coating, can also be processed in the reflow soldering process. SMD components are available loose or in blisters, depending on the shape. Surface mount device (SMD) components are used on PCBs to implement electronic circuits in a very small space. Unlike conventional components that are soldered onto PCBs, SMD components are soldered directly onto the surface of the PCB and do not have pins inserted or plated through the PCB.