Aer Day Sling 4 vs NIID FINO V Ultra-slim Tech Sling 2.5L
The Aer Day Sling 4 is 2.5L and 0.34kg0.7lb; the NIID FINO V Ultra-slim Tech Sling 2.5L is 2.5L and 0.33kg0.7lb. The NIID FINO V Ultra-slim Tech Sling 2.5L is 0.01kg0lb lighter. The Aer Day Sling 4 costs $10.010000000000005 less. The Aer Day Sling 4 fits the carry-on limit of 36 of 36 major airlines and the NIID FINO V Ultra-slim Tech Sling 2.5L fits 36; under the seat, 26 and 10 of 26.
| Spec | Aer Day Sling 4 | NIID FINO V Ultra-slim Tech Sling 2.5L |
|---|---|---|
| Price | $79Best | $89.01 |
| Volume | 2.5L | 2.5L |
| Weight | 0.34kg0.7lb | 0.33kg0.7lbBest |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 100%Best | 38% |
| Dimensions | 15×24×7.5cm6×9.5×3in | 22.5×42×3.5cm9×16.5×1.5in |
| Laptop | 8.3" | n/a |
| Opening | Main compartment opens wide | n/a |
| Warranty | Lifetime | 1 year |
| Organizer | Yes | Yes |
| Shoe compartment | No | No |
| Hydration sleeve | No | No |
| Frame sheet | No | No |
| Water-resistant | No | Yes |
| Rain cover | No | No |
| MOLLE | No | No |
| Hip belt | No | No |
| Sternum strap | No | No |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | No | No |
| Camera compartment | No | No |
| Material | 1680D CORDURA ballistic nylon exterior (bluesign approved), lightweight ripstop nylon interior (bluesign approved), YKK zippers, Duraflex hardware | Black: 100% Nylon; Gray: Eco-Polyester |
| Last checked | 2026-09 | 2026-10 |
Where their airline fit differs
| Airline | Limit | Aer Day Sling 4 | NIID FINO V Ultra-slim Tech Sling 2.5L |
|---|---|---|---|
| Air Arabia | Personal item | Fits | Too big |
| Air France | Personal item | Fits | Too big |
| AirAsia | Personal item | Fits | Too big |
| ANA (All Nippon Airways) | Personal item | Fits | Too big |
| Cebu Pacific | Personal item | Fits | Too big |
| KLM | Personal item | Fits | Too big |
| Lufthansa | Personal item | Fits | Too big |
| Norwegian Air Shuttle | Personal item | Fits | Too big |
| Ryanair | Personal item | Fits | Too big |
| SAS | Personal item | Fits | Too big |
| Singapore Airlines | Personal item | Fits | Too big |
| Turkish Airlines | Personal item | Fits | Too big |
| Vietjet Air | Personal item | Fits | Too big |
| Vueling | Personal item | Fits | Too big |
| WestJet | Personal item | Fits | Too big |
| Wizz Air | Personal item | 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.