Someone on a KZ forum site called Motion Pro about the cable lube, and he was told that it's not discontinued, just out of stock. Take that for what it's worth...
Personally, I use regular old motor oil. Make a funnel shape out of foil or a plastic bag, and rubber band it onto the end of the cable while sticking up. Fill the bag with oil, and it will slowly creep down the cable. Wait until you see some oil come out the bottom side.
Regarding oil not being necessary, all I can say is try oil on an old cable, then come back and post here again. It makes a noticeable difference. It may not be needed on a fresh cable, but it does help old ones.
Photo from revzilla...
https://www.revzilla.com/common-tre...PPga1tYbjBr27iUEqJWZ2KZEdjq8esxxStSmdaAdKMfLZ
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