If they are out of stock and someone needs some. A local guy has 7 of them for sale.
Have a look here to remedy any signal voltage and more https://giantscalenews.com/threads/fiber-optic-servo-extension.9792/Just a "heads up". This is probably more related to Futaba users but I imagine some others as well. I had the signal voltage on port/channel 6 drop to below 3 volts on an older 6014FS and the H50B that was plugged in freaked out and operated very erratic. I swapped to a newer 6014HS and operated all 5 servos in the normal and HS mode. Works great. The signal voltage was 4 volts on all 14 channels. I am considering going back to a Smart Fly board because they boost signal voltage to about 5.5 volts. Bottom line......Those who may use these servos in 35 cent and 42 cent air frames where servo extensions are quite long check to see that signal voltage is adequate (4volts or better).