1/8 scale lugnut wrench

[kulangflow]

This is probably a really easy question.

I'm working on my first 1/8 scale buggy and I can't figure out what to use to tighten the lugnuts. They're recessed enough that I can't get a regular sized socket in there. It appears that they're about 19mm. I tightened them as much as I could using the tools at hand but they almost immediately came loose under 4s power.

It's a Kyosho buggy that I bought from mwry. I'm assuming that all these 1/8 buggies probably use the same size lugnuts.

What are you guys using to tighten these buggers?

Thanks in advance!