The Peterbilt 579 12 Inch Seats Inc. Legacy Lo Seat Base Adapters are a practical solution for upgrading your pre-July 1st 2018 Peterbilt 579 Seats Inc. Legacy Lo Seating. Available in gloss black, these adapters are designed to fit most Peterbilt 579 seats and are offered in chrome or billet aluminum. With a 12-inch adapter, these seat base adapters provide a seamless and secure fit, ensuring comfort and stability during long drives. Upgrade your seating experience with these reliable and durable adapters.