Montane Tritium 40 vs Mountainsmith Zerk 40 UL Backpack
The Montane Tritium 40 is 40L and 0.9kg2lb; the Mountainsmith Zerk 40 UL Backpack is 40L and 0.97kg2.1lb. The Montane Tritium 40 is 0.07kg0.2lb lighter. The Montane Tritium 40 fits the carry-on limit of 14 of 36 major airlines and the Mountainsmith Zerk 40 UL Backpack fits 30; under the seat, 0 and 0 of 26.
| Spec | Montane Tritium 40 | Mountainsmith Zerk 40 UL Backpack |
|---|---|---|
| Price | n/a | $229.95 |
| Volume | 40L | 40L |
| Expands to | n/a | 44L |
| Weight | 0.9kg2lbBest | 0.97kg2.1lb |
| Carry-on compliance | 39% | 83%Best |
| Personal-item compliance | 0% | 0% |
| Dimensions | 54×32.5×23.5cm21.5×13×9.5in | 50.8×30.5×22.9cm20×12×9in |
| Laptop | sleeve, size not published | no laptop sleeve |
| Bottle pockets | 1 | 2 |
| Opening | Panel access, Large front compartment opening with internal compression | Roll-top, Roll top closure with V-strap compression |
| Warranty | Lifetime | Lifetime |
| Torso length | n/a | 40.6 to 53.3cm (16 to 21in) |
| Organizer | Yes | No |
| Shoe compartment | No | No |
| Hydration sleeve | No | Yes |
| Frame sheet | No | Removable |
| Water-resistant | No | No |
| Rain cover | No | No |
| MOLLE | No | No |
| Hip belt | No | Removable |
| Sternum strap | No | Yes |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | No | No |
| Camera compartment | No | No |
| Material | RAPTOR Balance 330 denier 100% recycled nylon, CONTACT Air Mesh, Halo lining | 210D and 100D Robic nylon X-Grid Extreema (UHMWPE) ripstop with UTS coating, Spundura stretch mesh, 150D polyester liner |
| Last checked | 2026-10 | 2026-09 |
Where their airline fit differs
| Airline | Limit | Montane Tritium 40 | Mountainsmith Zerk 40 UL Backpack |
|---|---|---|---|
| Air Canada | Carry-on | Too big | Fits |
| AirAsia | Carry-on | Too big | Fits |
| Alaska Airlines | Carry-on | Too big | Fits |
| American Airlines | Carry-on | Too big | Fits |
| Cebu Pacific | Carry-on | Too big | Fits |
| Delta Air Lines | Carry-on | Too big | Fits |
| JetBlue Airways | Carry-on | Too big | Fits |
| Lufthansa | Carry-on | Too big | Fits |
| Norwegian Air Shuttle | Carry-on | Too big | Fits |
| Qantas | Carry-on | Too big | Fits |
| SAS | Carry-on | Too big | Fits |
| Turkish Airlines | Carry-on | Too big | Fits |
| United Airlines | Carry-on | Too big | Fits |
| Vietjet Air | Carry-on | Too big | Fits |
| WestJet | Carry-on | Too big | Fits |
| Wizz Air | Carry-on | Too big | Fits |
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Specs come from each brand's own product page. Fit uses listed dimensions in any orientation. How we score carry-on fit.