All Rust Bullet coatings come in a gloss or satin finish, and we have not found any flattening agent that is compatible with our coatings that do not effect its performance. At this time, we do not have a matte/flat finish option, nor do we have any recommendations for lowering the sheen using a flattening agent. With the use of Tread-Tex (usually used on concrete applications for anti-slip), it will provide for a bit of gloss reduction on your finish, but will still not provide a matte finish to your coating.