Ninja Double Stack XL SL400UK

Name: Ninja Double Stack XL SL400UK
Brand: Ninja
SKU: 45159

Manufacturer: Ninja

The Ninja Double Stack XL is a basket-style air fryer built around two independent 4.75-litre cooking zones, giving it enough combined capacity to handle separate dishes at the same time. It covers six preset functions — air fry, bake, roast, toast, reheat, and dehydrate — and includes a dual zone sync feature that coordinates both baskets to finish cooking simultaneously. Digital controls keep operation straightforward, and a preheat function is on hand to bring the unit up to temperature before cooking starts.

Drawing 2470W during operation, the Double Stack XL works across a temperature range of 40°C to 210°C, accommodating a variety of cooking methods. It features dual heating elements and, notably, includes a viewing window for monitoring food without opening the basket, though there is no interior light. The baskets are dishwasher-safe for easier cleanup. Physically, the unit measures 280 mm wide, 470 mm deep, and 385 mm tall, with a weight of 10,300 g. There is no smartphone remote control or smart home compatibility, and the appliance carries a one-year warranty.

Pros

Dual-basket configuration with two 4.75-litre compartments allows separate dishes to be cooked at the same time
Dual zone sync coordinates both baskets to complete cooking simultaneously, removing the need to manually manage timing between zones
A viewing window lets users check on food progress without opening the basket, reducing heat loss during cooking
Six preset functions — air fry, bake, roast, toast, reheat, and dehydrate — provide broad cooking versatility from a single appliance
Dishwasher-safe baskets make cleanup after cooking more convenient
Preheat function allows the cooking chamber to reach the set temperature before food is placed inside

Cons

No interior light means the viewing window offers limited visibility in low-light conditions
At 10,300 g, the unit is heavy and not easy to move or reposition on a countertop
No shake reminders, so users must track manually when food needs to be turned or agitated during cooking
No smartphone remote control or smart home compatibility with Alexa or Google Assistant, ruling out any remote or voice-based operation
Warranty is limited to one year

Who is this for?

This air fryer is well matched to households that regularly need to cook multiple dishes simultaneously, with its two independent 4.75-litre baskets and dual zone sync making it straightforward to serve a full meal from one appliance. The viewing window adds practical value for users who prefer to monitor cooking progress without interrupting the process. The range of six preset functions also suits those looking to handle varied everyday tasks — from air frying and roasting to dehydrating — without relying on multiple kitchen appliances.

Who is this NOT for?

Users with limited counter space will likely struggle to accommodate the unit's 470 mm depth and 10,300 g weight, making it a poor fit for compact kitchens or those who need to store appliances between uses. Anyone who relies on smart home integration or smartphone control for convenience will find this model lacking, as it offers no connectivity with Alexa, Google Assistant, or any remote app. The absence of an interior light also means the viewing window is of reduced use in dimly lit environments, which may frustrate users who cook frequently in such conditions.

General info:

style	Basket
capacity	4.75 & 4.75 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	2470W
warranty period	1 years

The Ninja Double Stack XL is a basket-style dual-basket air fryer, with two 4.75-litre compartments offering a combined cooking capacity suited to preparing larger or multiple portions. It supports six preset functions — air fry, bake, roast, toast, reheat, and dehydrate — and operates across a temperature range of 40°C to 210°C. The unit draws 2470W during use and comes with 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 comes with dual zone sync and dual heating elements, coordinating both cooking compartments for simultaneous finishing. Digital controls handle all adjustments, and a preheat function is included to bring the fryer to the desired temperature before cooking begins. A viewing window allows food to be checked without opening the basket, though there is no interior light to assist visibility. Shake reminders are not available, and the fryer does not support smartphone remote control or integration with Alexa or Google Assistant.

Design:

has a dishwasher-safe basket/pot	✓
width	280 mm
thickness	470 mm
height	385 mm
weight	10300 g
volume	50666 cm³

The Ninja Double Stack XL measures 280 mm wide, 470 mm deep, and 385 mm tall, with a total volume of 50,666 cm³, which gives a practical indication of the counter space required. It weighs 10,300 g, a figure consistent with its dual-basket build. The baskets are dishwasher-safe, making routine cleaning more manageable after use.

Final Verdict

The Ninja Double Stack XL is a capable dual-basket air fryer that earns its place in larger households through its twin 4.75-litre cooking zones with dual zone sync, which take the guesswork out of timing separate dishes. The addition of a viewing window sets it apart from more basic configurations, giving users a degree of oversight during cooking that many will appreciate. It does carry a notable footprint and weight, and the lack of any smart connectivity keeps it firmly in the category of traditional appliance operation. For users whose main requirement is versatile, high-capacity cooking across multiple dishes without dependence on app control, the Ninja Double Stack XL represents a solid and well-rounded choice.