Once aftercoolers and separators have removed the bulk of the water, use these dryers to remove any remaining moisture in your air line. To reuse saturated desiccant, heat it in an oven at its reactivation temperature—you'll know it's dry when the color changes. Install these dryers after an oil filter to protect the desiccant.

Dryers with a clear bowl or a sight glass let you keep an eye on the contents inside. Dryers with a metal bowl are more durable than those with a plastic bowl, and they hold up to vapor better.