Boundary Supply Prima System vs KNKG APEX Backpack Medium
The Boundary Supply Prima System is 30L and 1.9kg4.2lb; the KNKG APEX Backpack Medium is 30L and 1.85kg4.1lb. The KNKG APEX Backpack Medium is 0.05kg0.1lb lighter. The KNKG APEX Backpack Medium costs $79 less. The Boundary Supply Prima System fits the carry-on limit of 35 of 36 major airlines and the KNKG APEX Backpack Medium fits 32; under the seat, 0 and 0 of 26.
| Spec | Boundary Supply Prima System | KNKG APEX Backpack Medium |
|---|---|---|
| Price | $279 | $200Best |
| Volume | 30L | 30L |
| Expands to | 38L | 35L |
| Weight | 1.9kg4.2lb | 1.85kg4.1lbBest |
| Carry-on compliance | 97%Best | 89% |
| Personal-item compliance | 0% | 0% |
| Dimensions | 53×30×18cm21×12×7in | 45×32×22cm17.5×12.5×8.5in |
| Laptop | 16" | 16" |
| Bottle pockets | 1 | 2 |
| Compression straps | 0 | n/a |
| Opening | Clamshell | Top-loading, Top lid style opening |
| Warranty | Lifetime | 25 years |
| Organizer | Yes | No |
| Shoe compartment | No | Yes |
| Hydration sleeve | No | No |
| Frame sheet | No | No |
| Water-resistant | Yes | No |
| Rain cover | No | No |
| MOLLE | No | No |
| Hip belt | No | No |
| Sternum strap | No | Removable |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | Yes | Yes |
| Camera compartment | Insert sold separately | No |
| Material | n/a | 1680D ballistic nylon body, ripstop nylon lining, YKK Vislon zippers, powder-coated steel hardware |
| Last checked | 2026-09 | 2026-10 |
Where their airline fit differs
| Airline | Limit | Boundary Supply Prima System | KNKG APEX Backpack Medium |
|---|---|---|---|
| Air Arabia | Carry-on | Fits | Too big |
| Air India | Carry-on | Fits | Too big |
| Qatar Airways | Carry-on | Too big | Fits |
| Ryanair | Carry-on | Fits | Too big |
| Vueling | 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.