On Feb 16, 9:18*pm, mm wrote:
I need an extension tube for 3/8" copper waterr tube

No you don't.

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What do people do in this situation?

See below.

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I've been to the store and good ole HDepot had lines, with IP at one
end, and a compression fitting at the other (although the label seemed
to say that it was compression at both ends.) *

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You have the proper stuff now. Take the input lines off the faucet and
the fix is obvious.

Joe

Joe