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 Reception Set R-106 Receiver Manual $7.99 Read more National NC-173 NC173 Radio Receiver Manual $10.49 Read more National NC-2-40D NC2-40D Radio Receiver Manual $9.99 Read more National HRO-50-1 HRO50-1 Radio Receiver Manual $12.99 Read more