---
url: "https://onebag.travel/compare/c0au43xw52/boundary-supply-prima-system-modular-travel-backpack/j0bvy2x3ap/tom-bihn-smart-alec/"
title: "Boundary Supply -- Prima System Modular Travel Backpack vs Tom Bihn Smart Alec"
description: "Boundary Supply -- Prima System Modular Travel Backpack vs Tom Bihn Smart Alec: capacity, weight, dimensions and how many airlines accept each as a carry-on…"
source: "https://onebag.travel/compare/c0au43xw52/boundary-supply-prima-system-modular-travel-backpack/j0bvy2x3ap/tom-bihn-smart-alec/"
---
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2.  [Carry-On Travel Backpacks](https://onebag.travel/carryons/)
3.  Boundary Supply -- Prima System Modular Travel Backpack vs. Tom Bihn Smart Alec

# Boundary Supply -- Prima System Modular Travel Backpack vs. Tom Bihn Smart Alec

Two carry-on travel backpacks, compared spec for spec.

## [Boundary Supply -- Prima System Modular Travel Backpack](https://onebag.travel/carryon/c0au43xw52/boundary-supply-prima-system-modular-travel-backpack/)

by [Boundary Supply](https://onebag.travel/carryons/?brands=Boundary Supply)

![Front facing view of the Boundary Supply -- Prima System Modular Travel Backpack](https://res.cloudinary.com/obt/image/upload/c_fill,w_400/v1619698435/carryons/Boundary_Supply_Prima_System_jsyefe.webp)

<table class="table table-sm cmp-spec mt-2"><tbody><tr><td>Capacity</td><td>22 L</td></tr><tr><td>Weight</td><td>1.4 kg</td></tr><tr><td>Dimensions</td><td>49×28×13 cm</td></tr><tr><td>Airline fit</td><td>92%</td></tr><tr><td>Price</td><td>$268</td></tr></tbody></table>

## Feature by feature

| Boundary Supply -- Prima System Modular Travel Backpack | Feature | Tom Bihn Smart Alec |
| --- | --- | --- |
| Storage |
| Y | Compression | N |
| 30L | Expanded Capacity | None |
| 0 | Opening | 0 |
| Y | Passport |  |
| Y | Passthrough | N |
| Carry |
| Y | Backpack | Y |
| removable | Hip Belt | removable |
| removable | Sternum Strap | removable |
| Inside |
| 17in | Laptop | 17in |
| 1 | Main Compartments | 0 |
| Y | Organizer | Y |
| Outside |
| × | Hard Shell | × |
| N | Rain-fly | N |
| 1 | Water Bottle Holder | N |
| Y | Water Resistant | Y |

<table class="cmp-material"><tbody><tr><td colspan="2">Material</td></tr><tr><td>Nywool, Nylon, Kodra Nylon</td><td></td></tr></tbody></table>

## [Tom Bihn Smart Alec](https://onebag.travel/carryon/j0bvy2x3ap/tom-bihn-smart-alec/)

by [Tom Bihn](https://onebag.travel/carryons/?brands=Tom Bihn)

![Front facing view of the Tom Bihn Smart Alec](https://res.cloudinary.com/obt/image/upload/c_fill,w_400/v1601600373/carryons/tombihnsmartalex_cvucd3.webp)

<table class="table table-sm cmp-spec mt-2"><tbody><tr><td>Capacity</td><td>26 L</td></tr><tr><td>Weight</td><td>0.9 kg</td></tr><tr><td>Dimensions</td><td>47×30×21 cm</td></tr><tr><td>Airline fit</td><td>74%</td></tr><tr><td>Price</td><td>$190</td></tr></tbody></table>

## Key differences between the Boundary Supply -- Prima System Modular Travel Backpack and Tom Bihn Smart Alec

-   **Compression straps:** Yes on the Boundary Supply -- Prima System Modular Travel Backpack; No on the Tom Bihn Smart Alec.
-   **Luggage passthrough:** Yes on the Boundary Supply -- Prima System Modular Travel Backpack; No on the Tom Bihn Smart Alec.
-   **Water bottle pockets:** 1 on the Boundary Supply -- Prima System Modular Travel Backpack; No on the Tom Bihn Smart Alec.

Both have: backpack straps, hip belt, sternum strap, laptop sleeve, built-in organizer, water resistant.

## Which airlines take each bag as a carry-on

We checked both bags against the carry-on size limits of 189 airlines. 138 accept both. 36 accept only the Boundary Supply -- Prima System Modular Travel Backpack, and 2 accept only the Tom Bihn Smart Alec.

### Only the Boundary Supply -- Prima System Modular Travel Backpack fits

Air Baltic, Air China, Air Malta, Air Niugini, Air Serbia, Air Seychelles, Asiana Airlines, ATA Airlines, Belavia, Blue Air, Bulgaria Air, China Eastern, Emirates Airlines, Enter Air, flybe, Great Lakes Airlines, Icelandair, InselAir, Juneyao Airlines, Luxair, Meridiana Fly, Nordwind Airlines, Royal Brunei Airlines, Ryanair, S7, Shandong Airlines, Shenzhen Airlines, Sun Express, TAP Air Portugal, TAROM, Tianjin Airlines (A320 & E190), TUI, Ukraine International, VIM Airlines (Closed), Volotea, Xiamen.

### Only the Tom Bihn Smart Alec fits

Regional Express, Virgin Australia.

## Boundary Supply -- Prima System Modular Travel Backpack vs. Tom Bihn Smart Alec: which should you pack?

The **Tom Bihn Smart Alec** carries 4L more than the **Boundary Supply -- Prima System Modular Travel Backpack** (22L vs. 26L), while the **Tom Bihn Smart Alec** is the lighter pack at 0.9kg (vs. 1.4kg). For carry-on flexibility, the **Boundary Supply -- Prima System Modular Travel Backpack** fits 92% of the airlines we track — the higher of the two. If you prioritise packing volume, choose the Tom Bihn Smart Alec; if you want to travel lighter, the Tom Bihn Smart Alec is the better call.