ATD Supply ATD2 vs Rains OTG Backpack
The ATD Supply ATD2 is 18L and 1.3kg2.9lb; the Rains OTG Backpack is 19L and 1.28kg2.8lb. The Rains OTG Backpack is 0.02kg0lb lighter. The Rains OTG Backpack costs $261 less. The ATD Supply ATD2 fits the carry-on limit of 36 of 36 major airlines and the Rains OTG Backpack fits 36; under the seat, 7 and 1 of 26.
| Spec | ATD Supply ATD2 | Rains OTG Backpack |
|---|---|---|
| Price | $456 | $195Best |
| Volume | 18L | 19L |
| Expands to | 31L | n/a |
| Weight | 1.3kg2.9lb | 1.28kg2.8lbBest |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 27%Best | 4% |
| Dimensions | 45×25×19cm17.5×10×7.5in | 46×32×12cm18×12.5×4.5in |
| Laptop | 15" | 15" |
| Opening | Roll-top, expandable roll top with Fidlock magnetic buckle, U-shaped back panel zip for top, side and clamshell access | front flap with c-clips over a magnetic main compartment |
| Warranty | Lifetime | 2 years |
| Organizer | Yes | Yes |
| Shoe compartment | No | No |
| Hydration sleeve | No | No |
| Frame sheet | Removable | No |
| Water-resistant | Yes | Yes |
| Rain cover | No | No |
| MOLLE | Yes | No |
| Hip belt | Removable | No |
| Sternum strap | Removable | No |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | Yes | Yes |
| Camera compartment | No | No |
| Bike-ready | No | No |
| Material | Challenge Sailcloth Ecopak EPLX600 waterproof laminate (100% post-consumer recycled polyester), RBC 200 lining, YKK zippers | Rains waterproof PU fabric (100% PES), 8,000 mm water column, TPU details |
| Last checked | 2026-10 | 2026-09 |
Where their airline fit differs
| Airline | Limit | ATD Supply ATD2 | Rains OTG Backpack |
|---|---|---|---|
| Allegiant Air | Personal item | Fits | Too big |
| American Airlines | Personal item | Fits | Too big |
| British Airways | Personal item | Fits | Too big |
| easyJet | Personal item | Fits | Too big |
| LATAM Airlines | Personal item | Fits | Too big |
| Volaris | Personal item | Fits | Too big |
Add more bags to this comparison
Specs come from each brand's own product page. Fit uses listed dimensions in any orientation. How we score carry-on fit.