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
Although both are great products, there is a flaw in the design of both the NV831 and NV835 dust canister. The mechanisms that hold the canister closed are weak and eventually break. That section needs to be made of metal, not plastic. Otherwise a great vacuum cleaner. I have 4 (we own a cleaning business). I do a maintenance clean each week and empty the canister after each clients home.
Hello Mark, thank you for sharing your experience. Have a good day.