KS Ultralight KS27 vs. Osprey Tempest 33

Two carry-on travel backpacks, compared spec for spec.

KS Ultralight KS27

Front facing view of the KS Ultralight KS27
Capacity27 L
Weight0.3 kg
Dimensions55×28×16 cm
Airline fit87%
Price$130

Feature by feature

KS Ultralight KS27FeatureOsprey Tempest 33
Storage
2 Compression 6
None Expanded Capacity None
0 Opening 0
top Passport top
N Passthrough N
Carry
Y Backpack Y
removable Hip Belt Y
removable Sternum Strap Y
Inside
N Laptop N
2 Main Compartments 2
N Organizer N
Outside
× Hard Shell ×
N Rain-fly N
2, side Water Bottle Holder 2, side
Y Water Resistant Y
Material
X-pac VX 07 YKK "waterproof zip"bluesign® APPROVED, 100% recycled 100D high-tenacity nylon w/ dobby check ripstop, DWR treatment made without PFAS

Osprey Tempest 33

Front facing view of the Osprey Tempest 33
Capacity33 L
Weight1.2 kg
Dimensions63×31×30 cm
Airline fit1%
Price$200

Key differences between the KS Ultralight KS27 and Osprey Tempest 33

Both have: passport pocket, backpack straps, water bottle pockets, water resistant.

Which airlines take each bag as a carry-on

We checked both bags against the carry-on size limits of 189 airlines. 2 accept both. 162 accept only the KS Ultralight KS27, and 0 accept only the Osprey Tempest 33.

Only the KS Ultralight KS27 fits

Adria Airways, Aegean Airlines, Aer Lingus, Aeroflot, Aerolineas Argentinas, Aeromexico, Air Asia, Air Astana, Air Baltic, Air Canada, Air Caraibes, Air China, Air Europa, Air France, Air India, Air Koryo, Air Macau, Air Malta, Air Mauritius, Air New Zealand, Air Nostrum, Air Serbia, Air Seychelles, Air Tahiti Nui, Air Wisconsin, AirAsiaX, Alaska Airlines, All Nipon Airways, Allegiant Air, American Airlines, ANA, Asiana Airlines, ATA Airlines, Atlas Global, Austrian, Avianca , Azerbaijan Airlines, Azul Linhas, Bahamasair, Bangkok Airways, Biman Bangladesh, Blue Air, Boliviana de Aviacion, British Airways, Brussels Airlines, Bulgaria Air, Cambodia Angkor Air, Caribbean Airlines, Cathay Pacific, Cayman Airways, Cebu Pacific, China Airlines, China Eastern, China Southern, CommutAir, Conviasa, Copa Airlines, Croatia Air, Cubana de Aviacion, Czech Airlines, Delta Airlines, Dragonair, EL AL, Emirates Airlines, Enter Air, Ethiopian Airlines, Eurowings, EVA Air, Fiji Airways, Finnair, Flair Air, flybe, Frontier Airlines, Garuda Indonesia, Gol Linhas Aereas, Great Lakes Airlines, Hainan Airlines, Hawaiian Airlines, Hong Kong Airlines, Iberia, Icelandair, Indigo, InselAir, Interjet, Iran Air, Iran Aseman Air, Island Air, Japan Airlines, Jet Airways, Jet2, jetBlue Airways, Jetstar Airways, Jetstar Asia, Juneyao Airlines, Kenya Airways, KLM, Korean Air, Kulula, Kuwait Air, LATAM , LOT Polish, Lufthansa, Luxair, Mahan Air, Malaysia Airlines, Mango, Meridiana Fly, Mesa Airlines, Middle East Airlines, Monarch Airlines, Nordwind Airlines, Norwegian, Onur Air, Pakistan International, Peach, PenAir, Philippine Airlines, Porter Airlines, Qantas Airways, Republic Airways, Royal Air Morocco, Royal Brunei Airlines, Ryanair, S7, SAS Scandinavian, Saudi Arabian Airlines, Shandong Airlines, Shenzhen Airlines, Sichuan Airlines, SilkAir, Silver Airways, Singapore Airlines, Sky Airlines, Skywest, Inc., South African Airways, Southwest Airlines, SpiceJet, Spirit Airlines, SriLankan Airlines, Sun Country, Sun Express, Swiss Int'l Air Lines, TAAG Angola, TAM Airlines, TAP Air Portugal, TAROM, Thai Airways, Tianjin Airlines (A320 & E190), Trans States, Travel Service Airlines, TUI, Turkish Airlines, Ukraine International, United Airlines, Ural Airlines, Uzbekistan Air, Vietnam Airlines, VIM Airlines (Closed), Virgin Atlantic, Volotea, WOW Airlines, Xiamen.

KS Ultralight KS27 vs. Osprey Tempest 33: which should you pack?

The Osprey Tempest 33 carries 6L more than the KS Ultralight KS27 (27L vs. 33L), while the KS Ultralight KS27 is the lighter pack at 0.3kg (vs. 1.2kg). For carry-on flexibility, the KS Ultralight KS27 fits 87% of the airlines we track — the higher of the two. If you prioritise packing volume, choose the Osprey Tempest 33; if you want to travel lighter, the KS Ultralight KS27 is the better call.