Thank you! I am one of the founders, the accuracy will vary depending on how the person is wearing it, but regardless it will be well within clinically acceptable values for something like physiotherapy or rehab.
Yoganotch itself is new (2020) but we've been building these devices for a few years - have a number of peer reviewed papers published based on Notch (https://wearnotch.com/papers).
Just wanted to take this as a chance to show what our company is doing: https://yoganotch.com - a smart yoga assistant, powered by wearable motion capture (which we have been producing for a while).
just launched this year. Happy to chat with anyone who is into quantified yoga.