National Coin Mechanism Service and Parts Manual. Covers Series 200 and Series 600 slug rejectors as well as Series 3300 and Series 3700 coin mechanisms.  Coin changers manufactured by National Rejectors are known as "Simplex Coin Changers.  These are electric coin mechs. This manual also covers the Simplex A3400, A3401, A3401-B, A3405-C.  It also covers the 4400 Series Penny Unit found on Vendo 83 and the Series 5500 from pre-war models of Mills.   Contains 36 pages.