Jason, your correct the coupling goes over the OD of the pipe. If I'm not mistaken in the USA "copper pipe" comes in straight lengths ,L,K,or M. Copper tubing comes annealed and in rolls. I do know the the fittings will work on pipe,not sure about tubing.The couplings are used for repair work where a shoulder at the mid point would prevent the coupling from being pushed up out of the way temporarily before soft soldering.
.mike
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