At this moment, the Shark DuoClean Powered Lift-Away Upright Vacuum Cleaner series includes model NV831 and NV835.
The difference between Shark NV831 and NV835 is the tools they include.
The NV831 comes with a Duster Crevice Tool, Pet Multi-Tool, and Pet Power Brush while the NV835 comes with a Duster Crevice Tool, Pet Multi-Tool, and Mini Motorized Brush.
If you wanna learn more about these accessories, you can visit Shark official site sharkclean.com to download manual.
Here is the link https://www.sharkclean.com/include/pdf/manual-NV830.pdf
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