This stainless steel bottle and straw top is ideal for transitioning from baby bottles. The two-piece silicone top can be used as a sippy or straw top. Includes: One stainless steel single-walled mason jar Silicone Sippy Straw Top Removable Silicone Straw Insert Plastic Ring & Cap Benefits: Single-wall stainless steel body - NOT double-wall and NOT insulated (lightweight for babies and toddlers - approx. 8oz with Sippy Straw, Plastic Ring and Cap attached) Flow controlled straw top to minimize mess Volume markings to 12 oz for daycare/bottle feeding compatibility Max capacity of 16 oz Easy-to-clean design—nowhere for mold to hide Dishwasher Safe Compatible with Mason Bottle Silicone Nipples and all other products Fits standard car cupholders