The tethered loop-top cap for 38 mm narrow mouth Nalgene bottles. Nalgene lists it as the “Narrow Mouth Cap”; the loop-top name is the trade name for the same part.

How it ships: this is the bulk-packed version — the lid itself, without a retail card or hang-tag. Same part, less packaging, which is the way we would rather sell a spare anyway.

What it fits

We are going to give you the thread rather than a model list, because Nalgene’s own page contradicts itself here. Their description says it fits “all Narrow Mouth and Oasis bottles.” Their compatibility field on the same page says “32 oz NM only.” Both cannot be true.

The defensible answer is the physical one: this is a 38 mm thread, and Nalgene’s narrow mouth bottles and the Oasis canteen share it — which is also how REI states the compatibility, covering the 16 and 32 oz narrow mouths and the Oasis. If you are matching an unusual or older bottle, ask us first.

It does not fit any wide mouth bottle. Narrow and wide do not interchange.

Specifications

• Cap thread 38 mm
• Screw top with tethered loop
• Materials LDPE and polypropylene
• Weight 1.6 oz (45.25 g)
• Free of BPA and BPS
• Dishwasher safe
• Made in the USA
• Dimensions — not published