Which two tools are often used in combination with each other for forcible entry and are referred to as "the irons"?

The tools commonly referred to as "the irons" in forcible entry operations are the flat head axe and the Halligan bar. This combination is widely recognized in the fire service for its effectiveness in breaching doors, windows, and other obstructions during emergency responses.

The flat head axe serves multi-functional purposes; it can be used for striking, prying, and even providing a point of leverage, while the Halligan bar, with its unique design, includes a forked end for prying and an adze end for cutting or striking. Together, they allow firefighters to quickly and effectively gain access to buildings, making them an essential part of the firefighter's tool kit when responding to emergencies where entry is required.

In contrast, the other combinations mentioned do not hold the same level of recognition or functional efficiency when used together for forcible entry. While tools like the pike pole, sledge hammer, and various types of axes are indeed useful in certain scenarios, they do not match the specific versatility and effectiveness of the flat head axe and Halligan bar as a duo in forcible entry scenarios.