What characteristic is essential when describing a body brush?

A body brush is specifically designed to have softer bristles, making it ideal for finishing work during grooming. This characteristic is essential because the body brush is used after the initial cleaning with coarser tools, allowing for a gentle touch that removes fine dust and adds a shine to the coat without irritating the horse's skin. Using softer bristles helps in maintaining the horse's comfort while effectively distributing natural oils in the coat, promoting a healthy appearance.

While there are other grooming tools that serve different purposes—such as hoof picks for cleaning hooves, or curry combs for removing heavy dirt—the primary function of a body brush focuses on the gentleness and finishing aspect of grooming rather than the initial cleaning.