Vintage First Source 1978-79 American Design Components catalog (softcover) for electro-mechanical equipment and components; contains black-and-white product illustrations, price tables and listings for precision potentiometers (10-turn, ganged), Helipot, Spectrol, Superior Electric Slo-Syn SS25-1189, Bodine KYC26A2, power modules and extended-range modules; catalog shows age-related wear including yellowed pages, light corner creases and moderate cover scuffing but pages are intact and readable, making it a useful reference for restorers, hobbyists and collectors.