They have actually mentioned both models in this review. Here is what it says: > We strongly recommend pairing a solar charger with a separate external USB battery bank so that you don’t have to ruin your gadgets built-in batteries by baking them in the sun during a charge cycle. Many of the products in this guide sell versions with and without a battery built into the solar charger. Although we prefer keeping the charger and battery separate, it’s not wrong if you pick the built-in battery version. It sounds like the thinking is that the built-in battery would lose capacity in the sun. If that’s the only reason, it’s only $5 more for the battery version of the Ryno at the moment, so maybe it’s worth it to still use an external battery but also use the Ryno’s built-in as a backup.