- 
            
Connector
The connectors are used to join axes or rods they are simple or triples - 
            
Arm Crank
Crank arm can be single, double, tapped or not - 
            
Bell Crank
Bell Crank can be simple or hub according to the built model - 
            
Coupling
The couplings are used to join 2 axles rods, a rod and a strip, a rod and a threaded rod between other uses