Mountainsmith Zerk 55 UL Backpack vs Simond MT100 Easyfit 50L Men's
The Mountainsmith Zerk 55 UL Backpack is 53L and 1.59kg3.5lb; the Simond MT100 Easyfit 50L Men's is 50L and 1.6kg3.5lb. The Mountainsmith Zerk 55 UL Backpack is 0.01kg0lb lighter. The Simond MT100 Easyfit 50L Men's costs $170.95 less. The Mountainsmith Zerk 55 UL Backpack fits the carry-on limit of 3 of 36 major airlines and the Simond MT100 Easyfit 50L Men's fits 1; under the seat, 0 and 0 of 26.
| Spec | Mountainsmith Zerk 55 UL Backpack | Simond MT100 Easyfit 50L Men's |
|---|---|---|
| Price | $279.95 | $109Best |
| Volume | 53L | 50L |
| Expands to | 58L | n/a |
| Weight | 1.59kg3.5lbBest | 1.6kg3.5lb |
| Carry-on compliance | 8%Best | 3% |
| Personal-item compliance | 0% | 0% |
| Dimensions | 61×27.9×22.9cm24×11×9in | 58×26×26cm23×10×10in |
| Laptop | no laptop sleeve | n/a |
| Compartments | n/a | 2 |
| Bottle pockets | 2 | n/a |
| Opening | Roll-top, Roll top closure with V-strap compression | n/a |
| Warranty | Lifetime | 10 years |
| Torso length | 40.6 to 55.9cm (16 to 22in) | n/a |
| Sizes | MD, LG | n/a |
| Fit | n/a | Men's |
| Organizer | No | No |
| Shoe compartment | No | No |
| Hydration sleeve | Yes | Yes |
| Frame sheet | Removable | Yes |
| Water-resistant | No | Yes |
| Rain cover | No | Yes |
| MOLLE | No | No |
| Hip belt | Removable | Yes |
| Sternum strap | Yes | Yes |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | No | No |
| Camera compartment | No | No |
| Material | 210D and 100D Robic nylon X-Grid Extreema (UHMWPE) ripstop with UTS coating, Spundura stretch mesh, 150D polyester liner | Polyester, water-repellent |
| Last checked | 2026-09 | 2026-09 |
Where their airline fit differs
| Airline | Limit | Mountainsmith Zerk 55 UL Backpack | Simond MT100 Easyfit 50L Men's |
|---|---|---|---|
| Frontier Airlines | Carry-on | Fits | Too big |
| Southwest Airlines | Carry-on | Fits | Too big |
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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.