The cap everybody loses. This is the 63 mm wide mouth loop-top — the tethered cap off a 32 or 48 oz Nalgene, sold on its own. Nalgene also sells it under the plainer name “Wide Mouth Cap”; it is 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

Nalgene’s own description says it “fits 32 & 48 oz Wide Mouth Bottles.” Their separate compatibility field is broader and also lists the All-Terrain, Grip-n-Gulp, On-The-Fly and On-The-Go bottles — all of which are built on the same 63 mm thread.

It does NOT fit the 16 oz wide mouth. That bottle is 53 mm and takes its own cap. Nalgene’s page metadata claims this cap “fits all wide mouth bottles,” and that line is simply wrong — we are flagging it because it is the single most common returned-item mistake in the range.

Specifications

• Cap thread 63 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

On the weight: 1.6 oz is Nalgene’s figure. It is also the figure they print on their narrow mouth cap, and REI lists the same part at 0.7 oz. Take it as approximate.

Nalgene’s leakproof guarantee on this cap rests on its threads — “continuous, straight shouldered semi-buttress threads keep the bottle sealed tight.”