Impel Rods stop rot. Rot thrives in moist, wet conditions. So, it's important to stop the cause of moisture in wood. And where there is rot or the need to prevent it, Impel Rods provide an economical, EPA approved and environmentally responsible way to deal with this threat. Impel Rods are formed from highly concentrated, water-diffusible borate, a naturally occurring element recognized internationally as an effective fungicide. Impel Rods resemble glass rods, and are available in various lengths and diameters, and will not discolor wood.