Tom Bihn Aviator T33 vs T35 Sling: Nylon or X-Pac for Everyday Carry

Introduction

Tom Bihn has a reputation for high-quality travel gear at reasonable prices, and the Aviator sling family is a good example of why. The lineup recently gained a new fabric option, which means there are now two closely related slings to choose between: the Aviator T33 in ripstop nylon and the newer Aviator T35 in waterproof X-Pac fabric. Each comes in two sizes, roughly 1.5 liters and 3.5 liters.

The designs are almost identical, so the real decision comes down to fabric, a small capacity difference, and how much space you need. This comparison walks through everything worth knowing before you pick one.

Tom Bihn Aviator T33 vs T35: The Naming, Decoded

Tom Bihn’s naming convention can be a little confusing. The two model names refer primarily to fabric, not size. The T33 is the ripstop nylon version, and it comes in both a smaller 1.5 liter size and a larger 3.5 liter size. The T35 is the newer update, built in X-Pac fabric with slightly modified details, and it is also offered in both sizes.

So the quick recap: T33 means nylon, T35 means X-Pac, and either name can describe the small or large version.

Capacity and Sizing

The two smaller models are both listed at 1.5 liters. Their length and width are basically identical, with only very slight differences in depth: the X-Pac T35’s main section is a touch wider than the nylon T33. Plugging the dimensions into a volume calculator gives about 1.5 liters on the nylon version and 1.6 liters on the X-Pac version, so in practice the difference is barely noticeable.

The same pattern holds for the larger bags. Full external dimensions work out to roughly 3.7 liters for the T33 and 3.9 liters for the T35, though interior padding and pockets eat up some of that volume. Real usable capacity sits close to the listed figures for both.

Materials and Water Resistance

The material split is the heart of this comparison. The T33 uses a ripstop nylon, while the T35 uses waterproof X-Pac fabric paired with YKK Aqua Guard zippers on the two main openings. Together that makes an extremely water-resistant sling, though not quite fully waterproof.

On durability, both versions were used heavily for several months each with no noticeable rips or tears. The lighter-colored nylon on the T33 does show dirt coloration, including what looks like a coffee stain on the bottom and discoloration around the top zipper. The X-Pac version has held up much better and still looks nearly brand new despite consistent use.

The trade-offs are clear: the nylon version is lighter and significantly cheaper, while the X-Pac version is more waterproof, more stain-resistant, and more durable thanks to a thicker, stiffer fabric plus an extra nylon panel on the bottom and back. The cost of that durability is a slightly heavier fabric and a price roughly $18 higher.

Pockets and Organization

Both models share essentially the same pocket layout, with a few extra sleeves on the larger sizes. The front pocket sticks out slightly from the main compartment, so it has its own volume that does not compete with interior space. All four variants include a sewn-in key leash in the front pocket, and the larger models add two extra fabric sleeves.

The back pocket is one of the standout features, well suited to smaller gear, cash, a travel wallet, a passport, or a phone. A Pixel 8 fits easily, as does an iPhone 15 in an OtterBox case, but mainly in the T35: although both small slings are the same length, the T35’s zipper is a little longer, so those phones fit only very tightly or not at all in the nylon version’s back pocket. On the larger model, the back pocket is enormous and swallows pretty much whatever you put in it.

Inside, both sizes have the same basic setup: a stretchy sleeve at the back and a stretchy zippered pocket at the front. The larger 3.5 liter versions add two more dividers and a significantly larger version of that front zippered pocket. The larger size also has a padded back sleeve that measures about 5.5 inches tall by 10 inches wide, roughly 13.5 by 19.5 cm, which fits an e-reader with a 7.75-inch screen snugly, and can accommodate an iPad mini or a Nintendo Switch. If you want to carry a tablet, the larger model is the way to go.

What Fits: Everyday Carry vs Full Day Out

The smaller 1.5 liter size works well as a basic everyday carry pouch. It comfortably swallows a phone, a battery pack, a small travel wallet, a passport, sunglasses, a small extra grocery bag in the front pocket, plus a charger, keys, and lip balm.

The 3.5 liter version doubles the space. It fits a tablet, an iPad mini, or a Nintendo Switch, and the stretchy back pocket accepts slightly bulkier items. There is also room for a smaller water bottle, and for a full day out you can add an umbrella or a light rain jacket on top of all the same small everyday gear.

Carry System and Strap

The carry system is simple and effective: a large adjustable webbing strap with a large Duraflex buckle, so nothing dangles loose. The larger model uses a slightly wider 1.5-inch webbing compared with 1.25 inches on the smaller 1.5 liter version.

It wears like a basic sling and works in front, side, or back carry, however you prefer. The strap is fairly long; at around two-thirds extended it sits comfortably, and near maximum length the bag hangs a bit lower.

Which Should You Buy?

Choose the Aviator T33 if you want the lightest, most affordable option and do not mind a nylon shell that shows dirt over time. Choose the T35 if water resistance, stain resistance, and long-term looks matter more, and you are willing to carry a little extra weight and pay roughly $18 more. On size, pick the 1.5 liter version for everyday carry and the 3.5 liter version if you want tablet, Switch, or water bottle capacity for full-day outings.

Conclusion

The Aviator T33 and T35 are near-twins separated by fabric. Both are thoughtfully organized, well-padded, and easy to carry in any position. The nylon T33 wins on weight and price; the X-Pac T35 wins on water resistance and durability. Match the fabric to your conditions and the size to your load, and either one makes a dependable everyday or travel sling.