Kuxiu has made some of my favorite Magsafe battery packs over the years. They were the first to give us a taste of the semi-solid state battery pack, which was ultra-efficient and kept safety in mind. They also brought one of the best features I’ve seen on any MagSafe battery pack: dual-sided MagSafe magnets, which let you add even more MagSafe accessories on top of the battery. Absolute genius. Now they are bringing us their brand new S4 Semi-Solid Safe MagSafe battery pack, and this might be their best one yet. Here is what you need to know.