A second class lever is a type of simple machine where the load is positioned between the effort and the fulcrum. This means that when you apply force (the effort) to one end of the lever, it lifts the load, which is in the middle, with the fulcrum located at the opposite end.
To better understand, imagine using a wheelbarrow. In this case, the wheel acts as the fulcrum, the load is the weight of the contents in the wheelbarrow (which sits in the middle), and when you lift the handles of the wheelbarrow (exerting effort), the load rises. This configuration allows you to lift heavier loads with less effort compared to using a first class lever.
Essentially, second class levers provide a mechanical advantage because the distance from the effort to the fulcrum is always greater than the distance from the load to the fulcrum. This means you can move heavier items more easily.