Ruling on Carrying the Dead on an Iron Bier

The question: Sa'd Muhammad al-Sa'id al-Maliki from Al-Imshan Middle School in the land of Bani Malik writes in his letter: From the land of Bani Malik to those whom it concerns, peace be upon you and Allah's mercy and blessings. And after that:
We inform you that in our mosque, there is a bier for carrying the dead and a washing bench made of iron and covered with plywood boards. We do not know if it is permissible to carry the dead on this type of iron. Please inform us, may Allah reward you with good, and may Allah preserve you and care for you?
Answer: We do not know of anything regarding this. Carrying the dead on wood, or on boards other than wood, or on iron, we do not know of anything regarding this. However, it is better to use something light so that it does not burden the bearers; because if people carry it on their shoulders, it may be difficult for them. As for if it is carried in a car, the matter is broad in this regard. But the light thing is better in all cases. Light boards are placed on the dead and carried on them to the cemetery; this is better than something heavy. As for the difficulty, there is no difficulty, if Allah wills, in it being made of iron or wood. But if it is light iron that does not burden people, there is no difficulty. And if it is heavy, it should be left so that it does not burden the bearers. Yes.