8PCS 10mm Silicone Straw Cover Cap for Stanley 40&30 Oz Cup for Reusable Straws
They are tight and do not fall off easily. Straw Cover for Stanley 40&30 Oz Cup, 10Mm Silicone Straw Covers Cap for Stanley Cup Accessories, Cute Cloud Flower Straw Topper for Tumblers, Straw Cap Stopper for Reusable Straws Tip Lids.