You dont even need those, just get outdoor 1/2" irrigation line, connect 1/4" irrigation line for each container.

At least that is what i did: here I use a 400 gph pump that was real cheap on Amazon. The 1/4" line goes right into the bucket. No reason i can think of for pressure regulation.

I got the lines and and the connectors at Home Depot, much cheaper since I figured out exatly what I wanted instead of buying a kit.