Autocross Trailer Box

Looking for a tote box for a HF trailer like the one pictured. I have tried Ace, Tractor Supply, Lowes, and Homidepo.
They may not make them any more ? Prefer something that is water tight... You know when we go to local regional events. ::Rain::

Any ideas?
Thanks.

http://www.topdownmx5.com/images/Trailer/DSCF0002.JPG

https://www.amazon.com/37-Portable-T...XNXCQKZ06B3VQ5https://images-na.ssl-images-amazon....L._SL1272_.jpg

Or WalMart.... Sorry...

https://www.walmart.com/ip/CONTICO-3...Black/40885402

Thanks for the leads. Now I know who makes it.