The SPDT rockers usually have three terminals and most likely used in pairs. These switches make or break the connection of a single conductor with either of two other single conductors. DPST rocker switches make or break the connection of two conductors in a single circuit, and usually have four terminals. The DPDT rocker switches make or break the connection of two conductors to two separate circuits. These usually have six terminals and are available in center off, momentary and maintained contact versions.