When I was a child, shuttling back and forth between the United States and summers with relatives in the Philippines, I carried two months’ worth of clothes in a small duffel so that I could use my checked suitcase to bring gifts back and forth across the Pacific. Back then, being a light packer meant traveling with only a carry-on. If you had told me that even overhead bin space would someday be at a steep premium, I’m not sure I would’ve believed you.

That was a long time ago, when airlines gave you complimentary fresh baguettes with tongs and little bottles of wine (not to children) on international flights. Now many affordable airlines, including Spirit and Allegiant, charge you extra even for carry-ons. In addition to saving you money, traveling with only a personal item means that you're not one of those clowns trying to rush the gate to make sure you get overhead bin space.

The perfect "personal item" is a bag that's sturdy and organized enough to carry everything you need for several days, but small enough to fit underneath the seat in front of you. After five years of development, the Trinity is one of Tom Bihn’s leading entrants in this category. As a convertible briefcase, it’s not that flexible, but if you travel frequently for work, it's the perfect choice.

Hardest-Wearing Wares

There are a few reasons why Tom Bihn consistently stays at the top of our Best Laptop Backpacks guide. There are bags that are cheaper, more stylish, or have more features, but none of them are made entirely in America, in one 16,000-square-foot location. It’s been a family-owned company for several decades, and direct oversight allows it to meet pretty exacting standards when it comes to manufacturing.

The Trinity is made from a heavy, abrasion-resistant 630-denier ballistic nylon, which is the same as my favorite backpack, the Synik. Just for fun, I once filled my Synik with cast-iron gym weights and dragged it around a parking lot, trying to tear through the fabric. It didn’t work. Rather than regular, small molded zippers—i.e., a zipper with teeth—the exterior zippers are coil zippers, like a Slinky. They have a gauge that’s about three times as big as any you might see in a regular daypack and are huge and run incredibly smoothly. You can stuff whatever you want in a compartment and the zipper is more likely to chop your finger off than get jammed.

The Trinity is called the Trinity because it has three main compartments and three ways to carry it. Two compartments open clamshell-style on either side, cushioning a slim work compartment with a laptop sleeve inside it. You can carry it as a backpack with shoulder straps; with an included shoulder strap at two attachment points; or with two padded grab handles, briefcase-style. Tom Bihn does suggest that if you want to carry it as a shoulder back, that you upgrade to the padded Absolute Shoulder Strap ($33), which is not included.

The second reason that people buy Tom Bihn bags is that the organization is thorough and completely unique to them, to the point where you can spend hours fiddling with different straps, O-rings, and pockets to find out the best way for you to use each one. Depending on your personality, this is either a huge plus or a very big minus. I did ask Tom Bihn what the first main compartment was for. The first main compartment has an optional fabric divider. It can zip along the interior of the compartment to divide it into two and doubles as a sleeve for a water bottle if you want to use this compartment as a gym bag.

The front of the bag also has three pockets, which work best for me when I’m carrying it as a briefcase. The main compartment on the front has the requisite Tom Bihn keychain lanyard, pen pockets, and small lip balm/headphone pockets. I miss these whenever I’m carrying a bag that doesn’t have them. It also has a luggage pass-through which fits on the handle of my Osprey roller bag. But come now, the point of this bag is that you’re not supposed to need a roller bag .

Small But Strong

At 21 liters, this bag has a relatively modest capacity. When carried as a backpack, it’s 16 inches tall and 11.4 inches deep when full. On my 6'4" colleague Julian Chokkattu, it looks like a normal-size bag, but I’m 5'2". When I met my friend at a coffee shop carrying it, she remarked that it looked like I was lugging my entire life through the streets of San Francisco.