I got this one. Fits like a glove, lots of protection. Really nice. https://www.amazon.com/gp/product/B01N590YOT/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Only real complaint is that it is a horizontal sleeve, I really wanted a vertical sleeve so that I could leave the sleeve in my bag and pull the PB out as needed. I think that this one https://www.amazon.com/gp/product/B078ZCY9HQ/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=A23FWTZ8UX6LWK would also be okay, but it might be a bit too snug, the next size up looks to be too large and it would move around too much for my liking.