This stainless steel screw top lid keeps contents in without exposing any part of it to plastic. Stainless steel neck, polypropylene#5 top for easy gripping. Fits both of our 1 liter (26oz.) and 1.5 liter (40oz.) stainless steel drinking bottles. Does NOT fit our 0.6 liter (20 oz.) tinted stainless steel bottles.