Answer:
insulators
Step-by-step explanation:
Insulators are any substance which do not let any heat to pass through it. In other words we can say that insulators are bad conductors of heat.
Example of insulators are clothes, woods, plastic
Blacksmiths work with metals which are heated at very high temperature. If the body of blacksmiths comes in contacts of metal with high temperature, they may get severe burn. To avoid any accidents they use clothes and gloves so in case if by mistake they come in contact with high temperature, these clothes and gear do not let let pass through it and protect the body of blacksmith.
Since these clothes and gloves do not let heat flow through it they belong to the category of insulators.