The Shark Lift-Away Pro Steam Pocket Mop S3901 and S3973 series, including S3973 S3973D,S3973WM, are similar items.

They can be used as a stick steamer for hard floor cleaning, or can be transformed into a handheld steamer for above floor cleaning. All of them are corded with 22-foot cable. They have 3 steam settings, dust,mop and scrub, for different cleaning needs.
The major differences between Shark S3901 and S3973 series are as follows.
1,Cleaner Head.
The S3901 uses Quick Release cleaning head for general sealed hard floor steaming, and this cleaner head can fit into a carpet glider to lightly steam carpet and rugs, however, it will not clean your carpet or rugs, just for grooming and freshening.)
The S3973 series use Intelli-Mop Head with Steam Blaster and Touch-Free Technology. With the Steam Blaster, you can direct the steam onto the tough stains which you want to clean, with the Touch Free feature, you do not need to touch the dirty pad to release it from the cleaner head after steaming. It does not have a carpet glider.
2, Power Specification
S3901
Voltage:120V, 60 Hz
Watts:1550W
Water Capacity:300 ml (10.14 oz.)
S3973 series
Voltage:120V, 60 Hz
Watts:1500W
Water Capacity:300 ml (10.14 oz.)
Attachments
S3901
Sold at Walmart,Best Buy,Kmart,Sears,Wayfair,etc..
Depends on where you buy it, it may include:
- Rectangular All-purpose Mop Head
- 2 Washable Rectangular Pocket Pads
- Filling Flask
- Direct Steam Nozzle
- Flat Scrubber Tool
- Accessory Hose
- Garment Steamer
- Squeegee Tool
- Detailing Brush
- Cylinder Cleaning Tool
- Squeegee Tool
- Wedge Tool
S3973WM
- Intelli-Mop Head with Steam Blaster
- 2x Double-Sided Dirt Grip? Pads
- 3 ft. Above-Floor Accessory Hose
- Garment Steamer
- Above-Floor Pocket Tool with Microfiber Pocket Pad
- Fill Flask
S3973D
- Intelli-Mop Head with Steam Blaster
- Double-Sided Dirt Grip? Pad
- 3 ft. Above-Floor Accessory Hose
- Garment Steamer
- Above-Floor Pocket Tool with Microfiber Pocket Pad
- Triangle Scrubber Head with Steam Blaster?
- Triangle Single-Sided Dirt Grip? Scrubber Pad
- Fill Flask
S3973
- Intelli-Mop Head with Steam Blaster
- 2x Double-Sided Dirt Grip? Pads
- 3 ft. Above-Floor Accessory Hose
- Garment Steamer
- Above-Floor Pocket Tool with Microfiber Pocket Pad
- Fill Flask
The Shark S3973 series Lift Away Pro Steam Pocket Mops are 2 in 1 versatile cleaners for steaming sealed hard floors,including sealed hardwood,laminate,marble,tile,stone floors, and above floor cleaning. You can easily detach the handheld steamer from the cradle to sanitize nooks and crannies, upholstery, toys, clothes, edges, corners, etc.
It has 3 steam levels for different cleaning tasks. The touch free feature allows you to release the double sided mop pad without touching it. Its steam blaster nozzle is designed to apply extra steam to stubborn messes.