The practical bottles for all applications Each Opening is 09 mm. They are more splash-free to use than the wide-necked bottles. Of course as well as being virtually indestructible, it is guaranteed to be leak-proof and really great for school, Camping, Hiking, cycling, Outdoor and free time. Our new Nalgene Sustain product line is made from Tritan Renew, 50% certified recycled content further off setting the use of fossil fuels and lowering greenhouse gas emissions. The same great Sustain water bottle made with material derived from 50% plastic waste now has a new look. Features: Nalgene Tritan Narrow Wide Mouth Plastic Water Bottle, 32 Ounce The practical bottles for all applications Each Opening is 09 mm. They are more splash-free to use than the wide-necked bottles. It is guaranteed to be leak-proof and really great for school, Camping, Hiking, cycling, Outdoor and free time. The same great Sustain water bottle made with material derived from 50% plastic waste now has a new look