Just bought it from ASUS UK shop. Its own page doesn't work, but it?s next to bottom in the acc list here:
https://shop.asus.co.uk/shop/gb/en-...let-Accessories/2279-Nexus-7-Accessories.aspx
https://shop.asus.co.uk/shop/gb/en-...let-Accessories/2279-Nexus-7-Accessories.aspx