Unlike any spray paint adapter on the market, the A1 adapter has an internal piece that allows male valved Rustoleum brand spray paint cans and other similar sized male valve cans to work with male caps and also make the caps function how they did on the old style female cans. Caps like Astro Fats, Pink Dots, NY Fats, German thins, and all other similar sized caps will work well on the adapter. It also works with the larger stemmed Rusto Fats, NY Thins, and Boston Thins/Fats but you have to firmly put the cap into the adapter before putting it on the can. The adapter is a single piece of hard plastic, so there is no gasket to fall apart like some other adapters. It also has a unique lip that makes it easier to change cans. It can also be used alone as a splatter cap. It comes with a New York Fat cap.