Half Shell Snugs are lighter and smaller and go perfectly with small earphones. Full Shell Snugs are larger but also give maximum grip and isolation for the ear. Why not Full Shells for everyone then? Well . Half shells still give a huge drop in external noise and are not only easier to store and carry but also work really well with many earphones. Some earphones really do require Full Shells to seat them properly and comfortably. Some uses for Snugs really require every last bit of isolation possible so again here Full Shells work better. In our compatibility guide we suggest which works best for all the earphone models we support.