I was intrigued by this
https://www.amazon.co.uk/gp/product/B01HCVIFZ6/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A2N58YCCQ NSUNR but didn't order it since I saw no space for the blue button at the back. Pity since I was very interested in the weight (82g), I liked the look (the dark colour), hoped the feel was better than the plastic, and didn't mind the absence of the sleep cover function which I don't use. I wrote to them about it since I think it misleading to advertise it as a Aura One cover.
The "ecological" tag is the usual ridiculous claim for something made mostly of synthetic material.