Omron provides through hole and surface mount options for low signal relays. Through hole means that the contact goes through the PCB and is soldered on the opposite side of the board. SMD (surface mount design) is the option shown above, in which case solder is put onto the PCB board and the contacts are set onto the solder and heated to make a connection. SMD saves space so that components can be placed on either side of PCB depending on the design of the circuit. Omron provides several families in SMD style. With inside bending terminal type it is possible to further decrease the mounting floor space; making it ideal for high density mounting. The example shown here of SMD illustrates the reduction in space that having the inside-L terminals can provide in an application where limited space is available.