What color is Part A in the sound deadener kit?

Silver. Part A is Mastercoat Permanent Rust Sealer Slim, but with a different label with instructions on how to use it with the sound deadener. It is meant to be used as an undercoat that seals and prevents rust, and also acts as a sound deadener and thermal insulator (with additive mixed in). Generally we add the sound deadener to the rust sealer, apply two coats, and then use a coat of AG111 in black as a topcoat. You can add sound deadener to the AG111 Satin black if you want, but if you want a black gloss finish, do not add the sound deadener to the gloss black because it dulls the gloss finish. Alternatively if sealing and preventing rust isn't a concern, you can add the sound deadener additive to another brand black paint.