Lowe Alpine AirZone Active 20 vs Mountainsmith Zerk 20 UL Daypack
The Lowe Alpine AirZone Active 20 is 20L and 0.77kg1.7lb; the Mountainsmith Zerk 20 UL Daypack is 20L and 0.79kg1.7lb. The Lowe Alpine AirZone Active 20 is 0.02kg0lb lighter. The Lowe Alpine AirZone Active 20 fits the carry-on limit of 1 of 36 major airlines and the Mountainsmith Zerk 20 UL Daypack fits 36; under the seat, 0 and 1 of 26.
| Spec | Lowe Alpine AirZone Active 20 | Mountainsmith Zerk 20 UL Daypack |
|---|---|---|
| Price | n/a | $179.95 |
| Volume | 20L | 20L |
| Expands to | n/a | 23L |
| Weight | 0.77kg1.7lbBest | 0.79kg1.7lb |
| Carry-on compliance | 3% | 100%Best |
| Personal-item compliance | 0% | 4%Best |
| Dimensions | 62×28×24cm24.5×11×9.5in | 45.7×25.4×15.2cm18×10×6in |
| Laptop | no laptop sleeve | no laptop sleeve |
| Bottle pockets | 2 | 2 |
| Opening | Top-loading, top lid | Roll-top, Roll top closure with V-strap compression |
| Warranty | n/a | Lifetime |
| Torso length | 48cm (19in) | 38.1 to 48.3cm (15 to 19in) |
| Organizer | No | No |
| Shoe compartment | No | No |
| Hydration sleeve | Yes | Yes |
| Frame sheet | No | Removable |
| Water-resistant | Yes | No |
| Rain cover | Yes | No |
| MOLLE | No | No |
| Hip belt | No | Removable |
| Sternum strap | Yes | Yes |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | No | No |
| Camera compartment | No | No |
| Bike-ready | No | No |
| Material | 50% recycled outer fabric with PFAS-free DWR | 210D and 100D Robic nylon X-Grid Extreema (UHMWPE) ripstop with UTS coating, 840D x 100D stretch mesh, 150D polyester liner |
| Last checked | 2026-09 | 2026-09 |
Where their airline fit differs
| Airline | Limit | Lowe Alpine AirZone Active 20 | Mountainsmith Zerk 20 UL Daypack |
|---|---|---|---|
| Air Arabia | Carry-on | Too big | Fits |
| Air Canada | Carry-on | Too big | Fits |
| Air France | Carry-on | Too big | Fits |
| Air India | Carry-on | Too big | Fits |
| AirAsia | Carry-on | Too big | Fits |
| Alaska Airlines | Carry-on | Too big | Fits |
| Allegiant Air | Carry-on | Too big | Fits |
| American Airlines | Carry-on | Too big | Fits |
| ANA (All Nippon Airways) | Carry-on | Too big | Fits |
| Avianca | Carry-on | Too big | Fits |
| British Airways | Carry-on | Too big | Fits |
| Cebu Pacific | Carry-on | Too big | Fits |
| Delta Air Lines | Carry-on | Too big | Fits |
| easyJet | Carry-on | Too big | Fits |
| Emirates | Carry-on | Too big | Fits |
| Frontier Airlines | Carry-on | Too big | Fits |
| Frontier Airlines | Personal item | Too big | Fits |
| Gol Linhas Aereas | Carry-on | Too big | Fits |
| IndiGo | Carry-on | Too big | Fits |
| JetBlue Airways | Carry-on | Too big | Fits |
| KLM | Carry-on | Too big | Fits |
| LATAM Airlines | 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 |
| Qatar Airways | Carry-on | Too big | Fits |
| Ryanair | Carry-on | Too big | Fits |
| SAS | Carry-on | Too big | Fits |
| Southwest Airlines | 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 |
| Volaris | Carry-on | Too big | Fits |
| Vueling | Carry-on | Too big | Fits |
| WestJet | Carry-on | Too big | Fits |
| Wizz Air | Carry-on | Too big | Fits |
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.