Hello August! Check out this Month's Specials.
The KTCX03-1 is an optional ±1 ppm (± 0.5 ppm typical) temperature-compensated crystal oscillator that replaces the standard crystal oscillator on the K3 Reference Oscillator board.
Q: When would I need to install the KTCXO3-1?
A: If you are planning on operating with transverters in the UHF or VHF ranges or some of the newest Digital Modes such as WSJT-X, JT65, FT8 or JT9, we recommend the KTCXO3-1.
KTCXO3-1 Installation Manual