3'' UNISEAL Flexible Tank Adapter Made in the USA (bulkhead)

Very pliable rubber and no leaks on my bog filter.

I love these products

couple years on a pond waterfall pipe connected to the side of a plastic pond tub you buy at hardware store. added flex seal for good measure. no leaks yet.

The hole needs to be precise, tight, and clean. It needs to be in a flat surface, no slants, no notches, grooves, etc. The material you are making a hole in needs to be reasonably thick/durable. Thin stuff may split or may just leak. The primary trick is to find a hole saw that doesn't leave a sloppy hole. Lightly sand it clean. Buy "Magic Lube", trust me you will thank me later.

Used these for building my pond and running pipe into a large induction tank and a 110 gallon black rubber animal water trough, and it was tough (impossible) for me (am weak girl) to get the pipes in until I figured out a trick. Pro tip: if you can, put the pipe in the freezer. I was lucky enough that each pipe was only a couple feet long and I stuck each one in the freezer for not very long at all, maybe a few minutes, less than half an hour anyways, and they slipped right in no problem! Probably could use ice if too long for the freezer.

This is a good product but it needs to be said that the 3 inch version is a total pia to get into the seal. We placed the tank on a wall and backed a vehicle up to the pipe to finally get it into the seal. I think the first seal might have been defective, it got cracked and ripped up after the insertion attempts. Luckily I bought two just in case and the second one we did the vehicle trick which worked well. No issues on the 1 1/2 or 1/2 seals. The three inch was a real pain. I hope it holds. Will test it next weak once the rest of the system is plumbed.

No issues. Would buy again. Actually I've already bought them twice. They're good.

Works