Skeleton box
Use skeleton box to render a skeleton loader in a size and shape not provided by skeleton avatar or text components.
A skeleton box can be any size or shape, and may be used to render a skeleton loader to replace content that cannot accurately be replaced by a skeleton avatar or skeleton text component.
For example, you may want to render a skeleton loader in place of a hero image in a content card that is still loading.
You may customize the width and height dimensions of the skeleton box to match the size and shape of the content it is replacing.
Refer to the loading pattern accessibility guidelines. Specifically, the secion about avoiding over-announcing loading states.