The Shark DuoClean Powered Lift-Away Speed by SharkNinja is an upright vacuum cleaner released in 2017. This device page includes troubleshooting and repair guides for the NV801 model, but should be applicable for most Lift-Away varieties.
I see on your site the post by Catie Halvorsen on how to replace belts on this model. Does she know what size these are and where to get them? Shark refuses to sell them to you.
