My parents have an in-sink soap dispenser. The unit is loose so that it wobbles and leaks water to under the sink.

The nut on the under side of the sink that secures the dispenser is loose. I tried to tighten it w/ my hands but I fear it's going to get loose again.

I have a basin wrench but I think the nut (1 7/8"?) is larger than the wrench (1 1/4"). It's a multi-tabbed plastic nut. I think the soap dispenser is similar to the unit shown here on amazon:

https://www.amazon.com/Moen-39...88519255&sr=8-7&th=1

What tool do I need to tighten this? Will this Rigid work?

https://www.amazon.com/gp/prod...&smid=A2ENTBEZKGXKVW

or this:

https://www.ridgid.com/us/en/ez-change-faucet-tool

or this larger basin wrench?

https://www.amazon.com/TEKTON-...88520128&sr=8-1&th=1

I have and use one similar to the Tekton, found a copy at Harbor Freight.

I'd just tighten ever six months. Or tighten it an put a tiny bit of silicone caulk on it. Like locktite but way easier to break free if needed. Be careful using tools on plastic threads/nuts.

Be careful tightening it too much they are just plastic nuts and all.

I've just always hand tightened them. They use the same nuts on facets also. I have had to use a telescoping basin wrench like your thrid link to get them off before when I couldn't get to them with channel locks.

Be careful as that wrench isn't made for that job. When I have used it to remove old ones I wasn't concerned if I damaged the nut or tread as long as I got it off.

We set those with silicone to prevent loosening. As for a tool the best and cheapest is a piece of pvc pipe a foot or so long the correct diameter with notches cut in the end to fit over the tabs on the nut. We also would drill a hole through the opposite end to run a screw driver through for extra torque but usually hand tight will do. Dont over tighten!

So best is to hand tighten w/ some loctite (or something similar)? Small dab of Elmers?

I'm not that strong, especially w/o leverage under the sink like this. Hand tight to you guys may mean the same as using the Tekton wrench for me.