These Shark cordless vacuum cleaners can be grouped into different series:
(1)IZ201UK,IZ201UKT,IZ251UK and IZ251UKT;
(2)IZ202UK,IZ202UKT,IZ252UK and IZ252UKT;
(3)IZ300UK,IZ300UKT,IZ320UK and Iz320UKT.
(4)IZ400UK,IZ400UKT and IZ420UKT
Each series includes single battery model, double-battery model and pet model.

The difference between Shark IZ201UK,IZ201UKT,IZ251UK and IZ251UKT are the color scheme, accessories, and numbers of batteries included.

• The IZ201UK is Orange & White, comes with (1) Dusting Brush, (1) 20cm Crevice Tool, (1) Upholstery Tool and one battery.
• The IZ201UKT is Teal, comes with all the tools IZ201UK includes and (1) Motorised Pet Tool for removing pet hair from upholstered surfaces, carpets, area rugs.etc.
• The IZ251UK is Ultraviolet, comes with (1) Anti Allergen Dusting Brush, (1) Dusting Brush, (1) 20cm Crevice Tool
  (1) Upholstery Tool and two batteries. It also includes a dual charging dock which can charge two batteries simultaneously.
• The IZ251UKT is Burgundy, comes with all the things IZ251UKT includes, and (1) Motorised Pet Tool.

On sharkclean.co.uk, the Anti Allergen Dusting Brush is priced at 14.99 pounds,
the Motorised Pet Tool is priced at 29.99 pounds,
the battery is priced at 79.99 pounds.

The difference between Shark IZ202UK,IZ202UKT,IZ252UK and IZ252UKT are the color scheme, accessories, and numbers of batteries included.

• The IZ202UK is Electric Blue, comes with (1) 20cm Crevice Tool, (1) Upholstery Tool and one battery.
• The IZ202UKT is Purple, comes with all the tools IZ201UK includes and (1) Anti Hair Wrap Pet Tool for removing embedded pet hair from upholstery.
• The IZ252UK is Fuchsia, comes with (1) 20cm Crevice Tool
  (1) Upholstery Tool and two batteries. It also includes a dual charging dock which can charge two batteries at the same time.
• The IZ252UKT is Peacock Blue, comes with all the things IZ252UK includes, and (1) Anti Hair Wrap Pet Tool.

The difference between Shark IZ300UK,IZ300UKT,IZ320UK and IZ320UKT are the color scheme, accessories, and numbers of batteries included.

• The Shark IZ300UK is Black and Copper, comes with (1) 20cm Crevice Tool, (1) Multi Surface Tool and one battery.
• The IZ300UKT is Black and Red,comes with everything the IZ300UK includes and a Powerfins Pet Tool.
• The IZ300UKTDB is Rose Gold, it is a limited edition model, comes with all the tools IZ300UKT includes and (1) Car Detailing Kit for cleaning your car or hard-to-reach areas around your home.
• The IZ320UK is Black and Silver, comes with (1) 30cm Crevice Tool, (1) Multi Surface Tool, (1) Anti Allergen Dusting Brush and two batteries. Also a dual battery charger for charging two batteries at the same time.
• The IZ320UKT is Black and Blue, comes with all the accessories IZ320UK includes and a Powerfins Pet Tool.

The difference between Shark IZ400UK, IZ400UKT and IZ420UKT are the color scheme, accessories, and numbers of batteries included.

• The IZ400UK is Charcoal Grey and Rose Gold, comes with (1) 20cm Crevice Tool, (1) Multi Surface Tool and one battery.
• The Iz400ukt is Charcoal Grey and Copper, comes with (1) Motorized Pet Tool, (1) 20cm Crevice Tool, (1) Multi Surface Tool and one battery.
• The IZ420UKT is Charcoal Grey and Silver, comes with (1) Anti Allergen Brush, (1) Motorized Pet Tool, (1) 30cm Crevice Tool, (1) Multi Surface Tool, two batteries and a charger for charging dual batteries.

The difference between Shark IZ201UK/IZ201UKT/IZ251UK/IZ251UKT, IZ202UK,IZ202UKT/IZ252UK/IZ252UKT and IZ300UK/IZ300UKT/IZ320UK/IZ320UKT is:

The Powerfins models IZ300UK/IZ300UKT/IZ320UK/IZ320UKT generate 50 percent more suction and picking up more dirt in one pass versus the none Powerfins models IZ201UK/IZ201UKT/IZ251UK/IZ251UKT, according to Shark product information.

The Powerfins models have a ECO mode to save battery power whereas the none Powerfins models do not have the ECO mode. While setting to the ECO mode, the vacuum can run up to 60 minutes.

The Powerfins models use a LED Smart Display to replace the small display on the none Powerfins models.
The LED Smart Display shows the remaining battery power,selected floor setting and suction mode, whereas the small display only shows the selected floor setting.

The IZ202UK,IZ202UKT/IZ252UK/IZ252UKT equipped with a combo brushroll whereas the other series use DuoClean which includes two brushrolls inside the cleaner head.

IZ300UK/IZ300UKT/IZ320UK/IZ320UKT vs IZ400UK/IZ400UKT/IZ420UKT
According to Shark, the IZ400UK/IZ400UKT/IZ420UKT feature Anti Hair Wrap Plus which uses the enhanced brush-roll design offers better hair pick up than the IZ300UK/IZ300UKT/IZ320UK/IZ320UKT.

The IZ400UK/IZ400UKT/IZ420UKT add the Anti-Odour Technology which is a cartridge system to protect against bad odours inside the vacuum.

The IZ400UK/IZ400UKT/IZ420UKT also have a
Clean Sense IQ mode which the IZ300UK/IZ300UKT/IZ320UK/IZ320UKT do not feature. This Clean Sense IQ mode automatically senses the dirt and adjusts cleaning power with optimised suction performance.

Read the comparison table for more information: