The difference between the SharkFLEX DuoClean Corded Ultra-Light Vacuum HV390, HV391 and HV392 are the color, included tools, and where sold.

The HV390 is charcoal gray and gold, sold on walmart.com, comes with a 12″ inch Crevice Tool, a Pet Multi-Tool, and an Accessory bag.

The HV391 is charcoal gray and gold, sold on amazon.com and bestbuy.com, comes with a Duster Crevice Tool, a Pet Multi-Tool, a MultiFlex Under Appliance Wand, and an Accessory bag.

The HV392 is charcoal gray and copper, sold on bedbathandbeyond.com and Shark official site sharkclean.com, comes with a Duster Crevice Tool, a Pet Multi-Tool, a Deep Cleaning Motorized Pet Tool, and an Accessory bag.

Otherwise, the HV390, HV391 and HV392 are the same.