The Poseidon Nano Power Bank is genuinely pocket-sized and I barely notice it in my jacket. It's waterproof, which is reassuring for outdoor use, and the MagSafe connection snaps on securely without a cable. It holds its charge for a long time, so I don't worry about it being dead when I grab it. It won't fully recharge a phone, but it gives enough of a top-up to get me home. Solid little EDC for daily carry and unexpected emergencies.