500ml Narrow Mouth Ultralite HDPE Water Bottle

The Nalgene 500ml Narrow Mouth Ultralite HDPE Water Bottle is a half-litre bottle (the 16oz model) with a 38 mm narrow neck, made from lightweight high density polyethylene for hikers who want a small bottle that pours cleanly. It weighs 63.75 g, stands 17.75 cm tall and measures 76 mm in diameter. The cap stays attached to the neck by a loop.

Who it's for

It is the small bottle for the days you do not need a litre, and the extra half litre that travels with your main bottles on a longer walk. The narrow neck suits anyone who wants to sip without slowing down.

Capacity and fit

Half a litre, in Nalgene's 16oz narrow mouth bottle. Next to the 500ml Wide Mouth Ultralite it is a touch bigger all round: 76 mm across against 70 mm, 17.75 cm tall against 16.5 cm, and 63.75 g against 56.75 g. You are choosing the neck, not the capacity.

The 500ml Narrow Mouth Sustain in Tritan Renew shares the 76 mm diameter and the 38 mm cap and weighs 106.25 g, so the Ultralite saves you 42.5 g. A scale in millilitres and ounces is printed on the back.

Drinking and refilling

A 38 mm neck gives a steady pour into a cup and an easy sip on the move. The cap closes on continuous semi-buttress threads, and its loop sits around the neck so the cap hangs from the bottle while you drink.

Cleaning and mould

You cannot get a hand inside a narrow neck, so clean this one by soaking. Fill it about two-thirds with very warm water, add a few drops of bleach, screw the cap on and shake, then let it stand for an hour. A bottle brush reaches the base and the inside of the cap. Rinse well and dry it completely with the cap removed: a bottle put away damp and closed is where smells and bacteria start. It can also go in the dishwasher, on the top rack.