What is a NATO strap?
A NATO strap is a single length of nylon that runs under the case of the watch and through the two spring bars of the watch, instead of two halves hooked to the lugs. Nothing to unscrew and no tool: the watch strap threads in from above. Because it passes under the case, the watch stays on the wrist even if one of the two spring bars breaks. It fits any watch whose lug width it matches; what changes is how the watch sits.
Measured references that take 18, 20 or 22 mm, the three widths most NATO straps are made in: 62.8% of the 41,485 watches in the database.
Which size: the lug width of the watch, nothing else
A NATO strap has no taper and no buckle end to size: one number decides it, the lug width of the watch, in whole millimetres. In the database, 20 mm is by far the most common (15,081 references, 36.4%), then 22 mm (6,971) and 18 mm (3,965). Odd sizes exist too: 1,919 references take 19 mm and 2,956 take 21 mm, and most NATO straps are not made in those widths. On an odd lug width, a watch strap one millimetre narrower sits loose in the gap, and one millimetre wider does not go in. Search your reference on this site for the measured number before buying.
What changes at the wrist
Two layers of nylon sit between the case back and the skin, so the watch rides about 1.5 mm higher than on a two-piece watch strap. On a thin dress watch that is visible; on a diver or a field watch it is not. The case also no longer touches the skin, which some people want in summer. And the watch strap does not need a spring bar tool to change, so it is the one people travel with and swap in a minute.
Where it makes sense, and where it does not
- Yes: sports, field and dive watches with standard lugs and a spring bar on each side, especially the 15,081 references at 20 mm and the 6,971 at 22 mm.
- Yes, with a thinner watch strap: watches with little room between the case back and the spring bar; a single-pass NATO strap, with one layer under the case, sits lower.
- No: the 2,640 watches in the database with an integrated bracelet, where the bracelet is part of the case and there is no lug width to match. Why no standard watch strap fits them.
- No: watches with fixed bars or with lugs too close to the case to pass two layers of nylon; their page on this site says when the lugs are drilled or the attachment is special.
The name, the material, the care
Where the name comes from (a British military stores code, 1973), what the nylon is made of and how a NATO strap is washed and kept are on the Milano Straps page about the NATO strap, where the straps are also made: NATO straps in recycled nylon and leather, 18 to 22 mm.
Check your own reference
Family averages are the reason people order the wrong size. Your reference has its own measured number, and it is in the database.
Search your referenceOther questions
- Why will no strap fit my watch?5.7% of watches have no lug width at all. Here is what to do instead.2,640
- What length watch strap do I need?Ready-made straps come in one length only. Whether that length reaches you is a different question.75/115 mm
- What size watch band do I need?The watch decides the width, your wrist decides the length. The three ways to find the width, in order, and the mistake to avoid.
- Which spring bar does my watch need?Length is the lug width of the watch; diameter is decided by the brand. Rolex, Omega and Tudor have their own, the rest take a standard 1.8 mm spring bar.