Forget Emptying. Enjoy Effortless Cleaning.

Take the hassle out of everyday cleaning with the Shark BU3521UK Cordless Stick Vacuum, featuring an innovative hands-free Auto-Empty System. Lightweight, powerful, and intelligently designed, this cordless vacuum automatically empties itself after every clean — so you can forget about emptying for up to 30 days.

Perfect for busy households, pet owners, and allergy sufferers, it delivers powerful performance across carpets and hard floors with minimal effort.

Hands-Free Auto-Empty System (Up to 30 Days)

Every time you dock the vacuum, Shark Clean & Empty automatically transfers dirt and debris into a large, sealed, bagless base unit:

• No manual emptying after every clean

• Holds dirt & debris for up to 30 days

• Fully sealed system keeps mess out of sight

• Simply dock and walk away

Ideal for cleaner hands, cleaner air, and total convenience.

Seals Away Dust & Allergens

Inside the base unit, fine dust is sealed away after every clean:

• Anti-Allergen Complete Seal captures up to 99.9% of dust, allergens & irritants*

• Helps keep allergens out of the air you breathe

• Perfect for homes with pets or allergy concerns

*Based on IEC standard 62885-2 CI. 5.14 (0.3–10 microns).

Lightweight & Easy to Manoeuvre

• 30% lighter* design for effortless handling

• Agile, cordless stick format makes whole-home cleaning easy

• Weighs just 2.7 kg in handheld mode

Enjoy powerful suction without the strain.

Powerful HyperVelocity Suction

• HyperVelocity accelerated suction delivers deep cleaning power

• Effective on both carpets and hard floors

• Picks up fine dust, debris, and pet hair with ease

Auto-Adjusting Floorhead with Anti Hair Wrap

• Brush-roll automatically adjusts speed between carpets and hard floors

• Maintains continuous contact on hard floors

• Anti Hair Wrap Technology actively removes hair from the brush-roll as you clean

• Ideal for homes with pets and long hair

Always Ready, Always Charged

• Docking station charges the vacuum while storing it

• Automatically empties when docked

• Up to 40 minutes runtime* per charge

• Battery fully recharges in 5 hours

*In Eco mode.

Clean Anywhere with Handheld Mode

Instantly convert to a handheld vacuum to clean above floors:

• Sofas, stairs & upholstery

• Car interiors

• Tight corners and edges

Included tools:

• Crevice Tool (20 cm)

• Pet Multi-Tool / Mini Surface Tool

Extend your reach with the wand for high-up cleaning.

Designed to Make Cleaning Easier

• LED headlights illuminate hidden dust and debris

• LED display shows battery life & power mode

• Quiet Mode lets you dock and charge silently, emptying later

• 3 power levels for customised cleaning

What’s in the Box

• Shark BU3521UK Cordless Stick Vacuum

• Auto-Empty Base

• Crevice Tool (20 cm)

• Mini Surface / Pet Tool

• Charging Dock

Specifications

General

• Product Type: Cordless Stick Vacuum

• Colour: White / Blue

• Dust Capacity (Vacuum): 0.42 L

• Filter Type: Anti-Allergen Complete Seal (base unit)

• Floor Types: Carpet & Hard Floors

• Pet Hair Cleaning: Yes

• Power Levels: 3

Battery

• Maximum Runtime: Up to 40 minutes

• Recharge Time: 5 hours

• Cordless: Yes

Dimensions & Weight

• Height: 76 cm

• Width: 37 cm

• Depth: 26.5 cm

• Weight: 5.39 kg

Shipping

• Shipping Weight: 9.91 kg

Warranty

• 5-Year Guarantee on main unit

• 2-Year Battery Guarantee
  (Registration required, UK & ROI only)

Why Choose the Shark BU3521UK?

• Hands-free Auto-Empty system (up to 30 days)

• Lightweight, cordless convenience

• Powerful HyperVelocity suction

• Auto-adjusting brush-roll for all floors

• Anti Hair Wrap Technology

• Excellent for pets & allergy-friendly homes

• Always charged, always ready

• Long Shark guarantee for peace of mind

The Shark BU3521UK Cordless Stick Vacuum with Auto-Empty System is the smarter way to clean — delivering powerful performance, effortless maintenance, and weeks of empty-free convenience.