Metal SmartStack I/O can only be stacked directly on the back of products supporting metal encased I/O models, such as: Classic OCS, RCS, RX ruggedized controller, and Metal FOX. Products are sorted by commonality.
Plastic SmartStack I/O can only be stacked directly on the back of products supporting plastic encased I/O modules. This includes the NX, QX351, Back Pack, Plastic FOX and RCX bases.
All SmartStack I/O modules include spring-clamp style removable terminals except where noted