The On-The-Fly is the Nalgene for the cab of the truck and the side of the pack. It is slimmer than the classic 32 oz, Nalgene lists it as fitting cup holders, and the lid opens with one hand and locks so it does not empty into your bag.

Nalgene calls the On-The-Fly top a lock-top / pop-top built for one-handed sipping that locks to prevent spills, and notes it is carabiner-friendly. That is the whole of what they publish about the mechanism — there is no spout dimension and no description of how the lock engages. We are not going to invent one.

Specifications

• Capacity 24 oz
• Cap thread 63 mm (wide mouth)
• Diameter 3 in (76 mm)
• Height 9.5 in (24.25 cm)
• Weight 4.63 oz (131.25 g)
• Fits cup holders
• Tritan Renew copolyester
• Free of BPA, BPS, BPF and phthalates
• Dishwasher safe
• Lifetime guarantee

A note on the mouth: Nalgene does not print the words “wide mouth” on this bottle. It is a 63 mm thread, which is the wide-mouth thread, and Nalgene’s own cap-compatibility data lists the On-The-Fly among the bottles its 63 mm caps fit. So wide-mouth caps fit it — that conclusion comes from Nalgene’s cap data, not from a line on the bottle page.

Cap interchange: this is a 63 mm wide-mouth thread, and Nalgene says plainly that its wide-mouth lids are interchangeable — you can swap an On-The-Fly top for a Grip-n-Gulp top or a plain loop-top cap as the need changes. The one exception in the range is the 16 oz wide mouth, which is 53 mm and takes its own cap.

About Nalgene Sustain and Tritan Renew

Sustain is Nalgene’s name for bottles molded in Tritan Renew, a copolyester that Nalgene describes as made with up to 50% certified recycled content. We quote that “up to” deliberately, because it is Nalgene’s own wording. The resin maker, Eastman, produces it by breaking plastic waste back down into the chemical building blocks of new plastic and accounting for the recycled share across production rather than tracing it to one individual bottle. That is how the certification works, and we would rather say so than imply something it does not cover.

Nalgene states in its FAQ that all of its bottles are free of BPA, BPS, BPF and phthalates.

Care

Dishwasher safe. Nalgene recommends the top rack, away from the heating element; if the bottle is too tall for the top rack, the bottom rack is fine on a high-temperature sanitizing cycle.

Hot liquids: Nalgene rates Tritan Renew for hot liquids including boiling water up to 212°F (100°C) in everyday use. You pour boiling water into the bottle; you never boil water in it, and these bottles are not made for direct heat or open flame. Nalgene asks you to wait a few seconds after pouring before screwing the lid down.

Freezing: allowed, but fill only about two-thirds so the contents can expand.

Origin: Nalgene lists this one as “China, USA” — the bottle is made in the USA and the cap is made in China. We quote it that way rather than badging the whole thing Made in USA.

Lifetime guarantee

Nalgene covers functional damage — cracks, breaks, broken components from normal intended use — under a Lifetime Guarantee. It excludes cosmetic damage such as scratches, nicks and worn printing, excludes lost or stolen items, and excludes Epic filtration products, which Nalgene routes to Epic Water Filters. Nalgene also states that claims are subject to review and may be rejected. Claims go through Nalgene with a photo and proof of purchase; they ask for 14 to 21 days.