I'm not sure of the kind of plastic, it usually feels like some kind of HDPE. I and others have had inconsistent results with SharkBite fittings for long-durat

I'm not sure of the kind of plastic, it usually feels like some kind of HDPE. I and others have had inconsistent results with SharkBite fittings for long-duration uses, for example see [1]. I suspect their O-ring is a potential weak link over a decades-span. YMMV. I like them for temporary (a few weeks to a few months) scenarios, but I haven't seen enough field experience like with PEX to know its design limits. I might use BoatLIFE Life Seal sealant in the future for the silicone if I run into another already-installed mini-split because I've seen it stand up very well to a massive amount of marine abuse in the short-term (3-5 years), but they don't warranty the sealant for longer than a year because of how much abuse it is normally put through, so I'd just be an n=1 experiment. Personally, the next time I will install a new mini-split or similar that has such a alternate drain arrangement, I'm going to do the following before the installer arrives. Flip the unit upside down so the pipe points up, drop some JB Weld putty into the bottom of the pipe, then fill the rest of the pipe with West System Epoxy to make it truly permanent and out-of-sight-out-of-mind for any possible extreme lifecycle of the unit. A friction-fit drain plug pointing out with the pull of gravity in a thermally-variant environment is just asking for trouble. If I had the right tools I'd probably fab up a replacement drain pipe out of stainless steel with threading to accept a silicone plug, and West System epoxy the pipe to the body of the unit, and see how that works. [1] https://www.contractortalk.com/f9/sharkbite-fittings-do-they-last-126571/ https://www.contractortalk.com/f9/sharkbite-fittings-do-they...