Paris trucks skate tool.
We use a skate tool every day here in the shop and this is one of our go-tos.
Solid metal, of course, Paris aren't playing around! The thing that makes this one different is that its a 3 piece tool - most are two, with the screwdriver/allen key being removable. With this one the whole tool comes apart and slots inside itself, making it much more pocket friendly than one stuck in a T shape.
No wide flange to protect your bearing shields with this one (check out the Independent or Carver tools for that) but if you leave the allen key in place, it should act as a stopper so that you can't overtighten your nuts.
As with all decent tools, it'll save you money in the long run over the plastic ones that strip out and murder turtles.
Keep those nuts tight and skate with a smile!