What is a stable rug used for?

It sounds like you're asking about a "stable rug" in the context of horses. A stable rug is a type of blanket used on horses for various purposes, including:

* Warmth: Stable rugs are designed to keep horses warm in cold weather, especially during the winter months. They come in various weights and materials depending on the temperature.

* Protection: Some stable rugs have a waterproof outer layer to protect the horse from rain and snow.

* Injury Prevention: Rugs can help prevent injuries caused by rubbing or irritation, especially in horses prone to skin conditions.

* Hygiene: Some stable rugs are designed for use during the shedding season to help remove loose hair and keep the horse clean.

If you're thinking of a rug for a different purpose, please clarify what you mean by "stable rug" so I can provide a more accurate answer!