Aluma-Hyde II Aerosol in Semi-Gloss Black is a popular firearm coating product offered by Brownells. It is a durable, heat-resistant, and corrosion-resistant coating designed to provide a protective and attractive finish to firearms and other metal surfaces. Aluma-Hyde II is typically used for refinishing or customizing firearms and offers a semi-gloss black finish. It comes in an aerosol can for easy application.