What is a mandatory component for leg-hold traps according to trapping regulations?

Leg-hold traps must include specific components to ensure compliance with trapping regulations and to promote animal welfare. The correct answer indicates that double chain swivels are a mandatory component for leg-hold traps. These swivels serve a critical function by allowing the trap to rotate freely when an animal is caught, which helps to minimize injury and stress to the animal. This design feature is important for preventing the trap from twisting in a way that could cause additional harm or discomfort.

In contrast, the other options do not reflect the mandatory components for leg-hold traps as outlined in trapping regulations. Rubber pads, while they can be used to cushion the trap's grip on an animal, are not a required component. Standard chains may be present on traps but do not offer the specific advantages of double chain swivels in terms of injury prevention. Plastic coating is not a recognized mandatory component and serves different purposes that do not directly align with the trap's essential requirements. Understanding these components is crucial for ensuring traps are both effective and humane in their function.