The Tooletries Shave Brush has premium synthetic bristles for two important reasons. Firstly, we love badgers. While most companies are dog friendly, we're badger friendly. Most days we have around seven badgers just wandering about the place, rolling over for belly rubs, and foraging outside for worms. So there's no way we could shave their bellies (the source of most bristles) just so you can shave your face. Secondly, synthetic bristles create a richer lather faster, so it's unlikely you'll ever encounter razor skip or drag while shaving.
No badger = better shave.