The line between the two is fuzzy. Generally, equipment is something easily available with modern technology, or something that helps the player feel cool and fleshed out and moves the story along, but doesn't grant any real bonus in combat or other challenges. Devices use super tech or magic or hand-wavy physics and usually offer a big boost.
In Cosmic Boy's case, he's from the future so the "super tech" issue is kind of moot. In his case (and with all the other Legionares), their gear is mostly to help keep the story rolling in a space-opera, sci-fi setting. Since almost everyone has access to flight and space survival gear and communicators, their flight rings and whatnot don't provide them any special advantage over a common mook, so in this setting they're equipment.
Giving all the same gear to a modern-day character would actually provide them a lot of advantages, since most people can't fly and don't have sealed atmospheric systems on-hand, so for a modern-day character, most of this gear would be Devices.
Ultimately, it's a GM call, based on the world.
Keep in mind, though, that Equipment is far easier to lose or destroy or be rendered otherwise useless. On of the tradeoffs for paying so little for it is that the GM is more free to have it cause problems or be unavailable. Legoinare flight rights are laughably known for how often they're blocked or jammed or simply don't function Planet X because of radiation B or somesuch.