WK IEASON 2Pcs Silicone Boot for Owala Water Bottle, Protective Flask Bottom Cover Base for Owala FreeSip Twist and Flip Flask Water Bottle Accessories-3.35inch Bottom Diameter

If anyone is looking in future, I ended up being happy with the black/pink two pack - https://www.amazon.com/dp/B0CYPWF68M?ref_=ppx_hzod_image_mob_b_fed_asin_title_0_0&th=1&psc=1