Katsuki goes with one of the smart phone types. He doesn't particularly care about apps right now. But it'll be easy to carry around and work with.

He pays close attention to what he's being shown. While he comes off like an angry, violent meathead type, he's actually very smart and a quick learner. He takes time to toy around with it a bit to make sure he knows how to navigate the menus. Then he's tucking it away in one of his pouches.

"Think I got it." He says. And then, because he's been trying to be a little more decent these days;

"Thanks."