Design
There are different kinds of wireless earbuds. In-ear ones go all the way inside your ear canal, while on-ear ones rest on it. Bone conduction buds, also known as running buds, usually rest outside your ears close to your cheekbone. Or they sometimes clip onto your cartilage like the Bose Ultra Open in the photo above.
The design you end up picking has to do with your personal preferences and lifestyle. If you’re specifically looking for running buds, bone conduction ones are a good option since they usually either go around your ear or clip onto them for a snugger fit. On-ear tips work much better for people like me with weird ears that don’t accept in-ear buds because they don’t keep popping out.