The switches are RoHS-compliant single-pole, single-throw (SPST) jumpers designed for surface mount PCB soldering. They feature a unique bifurcated contact design to increase electrical reliability.

The ADG7421F dual SPST switch provides the critical function of ... The simple functionality of the EVAL-ADG7421FEBZ is seen in its PCB implementation, with just one active device—the ADG7421F ...

The Double Pole Single Throw DPST relay is the equivalent of 2 SPST switches (NO Normally Open and NC Normaly Closed) and can be used to switch 2 different loads. As you can see in the schematics ...

is known as a "break" switch. The addition of an extra contact to an SPST switch lets it turn off one circuit and turn on another. This makes it a single-pole double-throw (SPDT) switch.