ISO waterproof box for battery

I know there are a lot of DIY battery box threads here, but I'm just looking for the waterproof box part, not the actual battery box details. This is what I have been using:

https://www.walmart.com/ip/Outdoor-Products-Large-Watertight-Case-Box-Blue/26674163

That box is no longer available from Walmart and, besides, it has some non-stainless metal parts in the hinges, and those rust like crazy. So, I'm looking for something waterproof that is going to last forever (or, at least longer than me).

My current battery is 6x4x2.5 (wxhxd) inches, and it would be nice to have a little extra space inside, as I have my current box rigged with 2 outlets, and even an input to connect to a solar panel for charging. I can manage drilling holes in the box and installing waterproof connectors, etc., so any waterproof box that is actually waterproof (and, of course, indestructible) will work.

If anybody has such a box that they'd recommend, LMK--bonus points of it does not cost a fortune...

The one you linked is the exact same one I have in my outback and it is, after 5 years, absolutely rusted and probably on its last leg, although still keeps the battery dry.  I also probably need to replace it as well.  If you find a good/better replacement, I would be interested in your take on it.  Like pretty much everything on my outback and AI, I look to you, Nowhereman to show me the way! 
 

I’ve been using these for the past couple years. So far so good. https://www.amazon.com/gp/aw/d/B07RVN91WB?psc=1&ref=ppx_pop_mob_b_asin_title

I’ve been using these for the past couple years. So far so good. https://www.amazon.com/gp/aw/d/B07RVN91WB?psc=1&ref=ppx_pop_mob_b_asin_title

That looks good, but I actually found this at Home Depot, which is half the price and also IP65 rated, all plastic (nothing to rust), so I think I'll give it a try:

https://www.homedepot.com/p/Husky-0-8-Gal-Professional-Duty-Waterproof-Storage-Container-with-Hinged-Lid-in-Red-261212/331254507

I was using one of the .30cal ammo boxes from Harbor Freight for a long time, but I wanted something a little more compact. The ammo box worked great though - waterproof, plenty of space for wiring/plugs/etc, and the handle on top made it easy to secure.

I ended up switching to the box you linked above, haha. Works great! I added a nylon strap to the loops to lash it down. I might end up mounting it in my front hatch, just to keep it out of the way, but then I have to go through the cable routing and through hull fittings situation again.

I might end up mounting it in my front hatch, just to keep it out of the way...

I put the battery inside the rear hatch of my Hobie, which is out of the way, and space that would otherwise be wasted...

My new battery box, made from the Home Depot waterproof box listed above. It just barely fits in the rear hatch, so I might movie it to the front. In any case, it looks like a winner!