One Dynaco Mark 3/Mark 2 upgrade board with parts and instructions. Each amplifier requires one board. The Board uses a Cascoded 12AU7 into a Long Tailed Pair Phase Inverter. Choose Capacitors in dropdown menu: Standard (Xicon), or Solen. NOTE: The board is Pictured with Solen Coupling Capacitors, you will receive Xicon Polypropylene Capacitors with the Standard Kit. MADE IN USA mk3boardsparts$129.95Version: Board with Parts XiconBoard with Parts Solen (+$28.00)Just Parts No Board (-$38.95) Instructions Pages 1-12 Instructions Pages 13-22 Mark 2, 3, & 4 Appendix Triode, USA Customer Service M-F 9AM-4PM CT 1-800-774-3201 Email us Anytime: questions@triodestore.com