Which Class of Lever is it?
Depends on whether you are setting it or it catches a mouse. When you set it, it is a second class lever since the spring (resistance) is between the fulcrum (pivot) and the working force from your finger to set it. When it is tripped and springs it becomes a third class lever, since the force (spring) is now between the fulcrum and the end of the wire snapper which hits the mouse. Hope this helps.
