National Horizon 20 HiFi Amplifier Manual Sorry, this product cannot be purchased. $8.99 Category: National Description Description For sale is reprint of National Horizon 20 HiFi Amplifier Manual. Manual is 8 pages Includes Part List and Circuit Diagram. Manual also includes 2 Service Bulletins Hi-Fi-8 and Hi-Fi-9 Related products National HRO-5 HRO-5T HRO-5R HRO HRO-SR Receiver Manual $10.49 Read more National NC-125 NC125 Radio Receiver Manual $9.99 Read more National NCX-3 NCX3 HAM Transceiver Manual $9.99 Read more National NC-44 NC44 Radio Receiver Manual $5.99 Read more