First it was bucket bags, then it was backpacks. But belt bags make so much more sense, so it’s a great thing they're back in favor. The ubiquitous cross-body bag, with its straps and chains, looks like a ball and chain in comparison to this hands-free baby, also known as a fanny pack, the purse world’s answer to Bluetooth.

If you’re wondering why belt bags are referred to as fanny packs, it’s because initially, they were meant to be worn toward the back, where the “fanny” is. When it became clear this was awkward and too easy to pickpocket, the waist bag took a 180-degree turn. This led to whole other set of issues, including the fact that fanny refers to a woman’s private parts in other English-speaking countries.

Of late, belt bags have slowly been sneaking into the repertoire of chic. If you get one now, you’ll not only be a couple steps ahead of the fashion curve, you’ll also have two free hands to use for whatever floats your boat. Like eating an ice cream cone while texting you BFF.  Or applying lipstick while trading stocks on your iPhone. If that isn’t awesome, I’m not sure what is.

But make sure to...

Choose a structured version to elevate the casual style. Here are a few of our favorites.

Clockwise from bottom left: Stella McCartney Shell Belt Bag, $60; Claire VivierNubuck Belt Bag, $195; Claire Vivier Shearling belt bag, $280; Alexander Wang Black Leather Belt Bag, $495; Newbark Eva Snake Effect Belt Bag, $1,200, Rebecca Minkoff Affair Fanny Bag, $195.

And...

Avoid centering it. Just off to the side is fine, thanks—or else, this could happen: