Factory AC Drain Question

Can someone please tell me how the factory AC evaporator drain connects to the engine side of the firewall rubber drain? Is there a plastic tube that shoves into the rubber drain tube?

I ask because I am installing a Custom Auto Air retrofit in a non-factory AC car and I do not like their method of fabricating the drain tube...they have a clear poly tube that runs from the AC drain in the cabin straight forward to the engine side of the firewall and that just looks hockie...

I bought this...

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