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 NCX-5 NCX 5 Transceiver Manual $11.50 Read more National NTX-30 Radio Transmitter Manual $9.99 Read more National HRO-5 HRO-5T HRO-5R HRO HRO-SR Receiver Manual $10.49 Read more National HRO Reception Set R-106 Receiver Manual $7.99 Read more