Contain your power source... these guys surely did. Transformer's Energon cubes, Stark's arc reactor & Avatar's Unobtanium
This battery holder is by far the easiest way to add a battery to a small wearable project.
This tiny coin cell battery holder is ideal for small portable or wearable projects. It holds two 20mm coin cells (2032 are the most popular size) in series to generate 6V nominal.