TurboVS
Ninja Double Stack XL SL451 specifications and in-depth review

Ninja Double Stack XL SL451

Manufacturer: Ninja

The Ninja Double Stack XL SL451 is a basket-style air fryer built around a dual-drawer design that gives cooks two independent 5-litre compartments to work with simultaneously. Running on 1690W, it supports six cooking modes — air fry, bake, roast, toast, reheat, and dehydrate — covering a broad range of everyday cooking tasks within a single appliance.

Both drawers operate with separate heating elements and dual zone sync functionality, allowing each compartment to be managed independently or coordinated to finish at the same time. The temperature range spans from 40°C to 210°C, digital controls handle all adjustments, and a preheat function is included. The baskets are dishwasher-safe, and the unit measures 488 mm wide, 286 mm deep, and 385 mm tall, with a total weight of approximately 12 kg. It carries a one-year warranty.

Pros
  • Dual-basket design with two separate 5-litre compartments allows two different foods to be cooked simultaneously
  • Dual zone sync coordinates both drawers to finish at the same time, reducing the need to monitor cooking separately
  • Six preset functions — air fry, bake, roast, toast, reheat, and dehydrate — cover a wide range of cooking tasks in one appliance
  • Wide temperature range from 40°C to 210°C provides flexibility across different cooking methods
  • Dishwasher-safe baskets make post-cooking cleanup straightforward
  • Preheat function available for more consistent cooking results
Cons
  • No viewing window, so checking food requires opening the drawers
  • No interior light, limiting visibility when inspecting contents
  • No shake reminders to prompt food turning or tossing during cooking cycles
  • No smartphone app or smart home integration, ruling out remote monitoring or voice control
  • At 12,020 g and 488 mm wide, the unit occupies significant counter space and is not easy to move around
Who is this for?

This air fryer works well for households that regularly cook for several people at once, thanks to its dual 5-litre compartments that allow two different dishes to be prepared simultaneously. The dual zone sync feature makes it particularly practical for those who want both portions ready at the same time without constant monitoring. Users who cook a variety of foods will also benefit from the six preset functions spanning air frying, baking, roasting, toasting, reheating, and dehydrating, all within a single appliance. The dishwasher-safe baskets add further appeal for anyone who values easy cleanup after cooking larger meals.

Who is this NOT for?

Those with limited kitchen counter space will find the 488 mm width and 12 kg weight difficult to accommodate, as the unit is large and not easy to reposition frequently. Users who prefer to monitor food visually during cooking without interrupting the cycle will be at a disadvantage, since the appliance has no viewing window and no interior light. Anyone looking for smart home integration or remote control via a smartphone app will also find this model unsuitable, as it lacks connectivity with Alexa, Google Assistant, or any mobile platform.

General info:

style Basket
capacity 5 & 5 l
is a dual-basket air fryer ✓
preset functions Air fry, Bake, Roast, Toast, Reheat, Dehydrate
number of functions 6
maximum cooking temperature 210°C
minimum cooking temperature 40°C
operating power consumption 1690W
warranty period 1 years

The Ninja Double Stack XL SL451 is a basket-style air fryer with a dual-drawer configuration, each compartment holding 5 litres for a combined 10-litre capacity. It offers six preset cooking functions — air fry, bake, roast, toast, reheat, and dehydrate — with a temperature range spanning 40°C to 210°C. Operating at 1690W, it draws a moderate amount of power for its size, and comes backed by a one-year warranty.

Features:

has dual zone sync ✓
has dual heating elements ✓
has digital controls ✓
shake reminders None
has a window ✕
has a preheat function ✓
has an interior light ✕
supports a remote smartphone ✕
works with Alexa ✕
compatible with Google Assistant ✕

The unit includes dual zone sync and dual heating elements, allowing both compartments to be coordinated or run independently, and all adjustments are handled through digital controls. A preheat function is also available. There are no shake reminders, and the fryer does not feature a viewing window or an interior light. Smartphone control is not supported, and the appliance is not compatible with Alexa or Google Assistant.

Design:

has a dishwasher-safe basket/pot ✓
width 488 mm
thickness 286 mm
height 385 mm
weight 12020 g
volume 53733.68 cm³

The appliance measures 488 mm wide, 286 mm deep, and 385 mm tall, with a total volume of approximately 53,733 cm³, making it a notably large unit suited to counter spaces with adequate room. It weighs 12,020 g, and the baskets are dishwasher-safe, simplifying the cleaning process after use.

Final Verdict

The Ninja Double Stack XL SL451 is a capable, full-featured air fryer built around the practical advantage of dual independent 5-litre baskets with zone sync, making it a strong fit for households that regularly prepare multiple dishes at once. Its six cooking functions and broad temperature range give it genuine versatility across everyday cooking tasks, while the dishwasher-safe baskets keep maintenance manageable. It does come with trade-offs — the large footprint demands dedicated counter space, and the absence of smart connectivity or a viewing window will limit its appeal for some users. Overall, the SL451 is a well-specified appliance for those whose priority is cooking capacity and multi-function flexibility rather than compact form or connected features.

Popular Comparisons

Ninja Double Stack XL SL451
Ninja Double Stack XL SL451
VS
Ninja Double Stack XL SL400UK
Ninja Double Stack XL SL400UK