The short answer: most watch straps have holes about 6mm apart, so one hole is often too tight and the next too loose. A micro-adjust buckle or link adds a second position about 3mm away, roughly half a hole, which doubles the number of usable fit positions on the strap you already own. Changing between the two takes no tools.
You can add micro-adjust to a leather, rubber, or fabric strap in two ways. Replace the strap's pin buckle with a micro-adjust buckle like the Fitwell M1, or keep your buckle or deployant clasp and add an inline micro-adjust link like the Fitwell M4.
Why a watch strap ends up between holes
Bracelets usually come with some way to fine-tune the fit. Straps mostly don't. A typical strap gives you a fixed set of holes spaced around 6mm apart, and the right fit for your wrist often sits somewhere in between.
Your wrist isn't a fixed size either. It changes over the course of a day, and it changes with the weather. A strap that's right in the morning can feel tight on a warm afternoon or after exercise, and loose again on a cold day. That's why so many people end up with a watch that's one hole too tight and the next too loose, and why some stop wearing a watch they love.
Your options, compared
| Option | What it does | Good for | Trade-offs |
|---|---|---|---|
| Punch an extra hole | Adds one more fixed hole between two existing ones. | A single fit that never changes, on a leather strap you don't mind modifying. | Permanent. Holes set close together can weaken the strap and look homemade. It's still one fixed position, so it doesn't help when your wrist changes through the day. |
| Micro-adjust buckle (Fitwell M1) | Replaces the strap's pin buckle with one that has two positions 3mm apart. | Leather, rubber, and fabric straps with a standard pin buckle on a spring bar. | Replaces the original buckle. Installs with a spring bar tool. |
| Inline micro-adjust link (Fitwell M4) | Sits between the strap and its existing buckle or deployant clasp, adding the same 3mm of adjustment. | Deployant clasps, its most common use: it's designed to fit most of them. Also branded buckles you want to keep. | Adds about 5.5mm of length (less than one hole). Adjusted by hand with the watch off, in five or ten seconds; no tools. |
| Micro-adjust deployant | A folding clasp with adjustment built in. | Anyone who wants a deployant clasp anyway. | Ordinary deployants have no micro-adjust, so it has to be built for it. Delugs' micro-adjust CTS clasp uses the Fitwell mechanism. If you already have a deployant you like, the Fitwell M4 link is designed to fit most of them. |
Bracelets are a different case: most have their own fine-adjust holes or half links, so this guide is about straps.
How a micro-adjust buckle works
The Fitwell M1 replaces your strap's buckle and has two fixed positions, 3mm apart. Pull the buckle out to loosen it; press it in to tighten it. No tools, just your fingers. With holes about 6mm apart, that extra position lands halfway between two holes, so every hole on the strap now gives you two fits instead of one.
The action is deliberately firm. It holds because changing it isn't casual, so the buckle stays where you put it under the weight of the watch. Once you get used to it, you can adjust it on the wrist.
The M4 link uses the same two positions, 3mm apart, but sits between the strap and the closure you already have. To change it, take the watch off, move the slide, and put it back on. It takes five or ten seconds.
Which one fits your strap?
Choose the M1 buckle if…
- Your strap has a standard pin (tang) buckle held on by a spring bar.
- You're happy to swap the original buckle out.
- You want to adjust on the wrist.
- The strap is 16mm, 18mm or 20mm at the buckle end. 22mm is coming later this year.
Choose the M4 link if…
- You want to keep the original buckle, such as a branded one.
- Your watch closes with a deployant clasp. That's what the M4 is most often used for, and it's designed to fit most of them.
- You've run out of holes on a strap you like.
- The strap is 16mm to 22mm at the closure.
Measure the strap width at the buckle end, not between the lugs; most straps taper. You'd pick one per watch, not both on the same strap. If you're not sure, the size finder walks you through it.
Questions people ask
Can you add micro-adjust to a leather watch strap?
Yes. If the strap has a pin buckle on a spring bar, swap the buckle for a micro-adjust buckle such as the Fitwell M1. If you want to keep the buckle, add an inline link such as the M4 instead. Neither requires modifying the strap.
Is there micro-adjust for a rubber watch strap?
Yes. The same two options apply to rubber straps, and neither means punching a permanent hole in the rubber.
Should I just punch another hole in my strap?
It works if you want one new fixed fit and don't mind a permanent change. If your wrist changes size during the day or with the weather, a second fixed hole won't solve it; two positions you can switch between will.
How much adjustment does a micro-adjust buckle give?
The Fitwell M1 and M4 both move 3mm between two fixed positions. On a strap with holes about 6mm apart, that's half a hole.
Will it slip to the loose position on its own?
It's designed not to. The action is deliberately firm, so it stays in the position you set and takes a positive push to change.
Do I need tools?
Not to adjust it. Switching between the two positions is tool-less: you do it by hand. Fitting it to the strap the first time takes a spring bar tool, with no modification to the strap. Step-by-step videos are on the M1 installation and M4 installation pages.
Does it work with a deployant clasp?
Yes. The M4 link is designed to fit most deployant clasps, and that's what it's most often used for. It also works with pin buckles. The current version doesn't fit Omega deployant clasps or Panerai. See adding micro-adjust to a deployant clasp for details.
About Fitwell
Fitwell makes micro-adjust buckles and links for watch straps, precision-machined in 316L stainless steel and titanium, with patented micro-adjust technology. Awake, Sherpa, Delugs, Kuoe and Junkers are among the watch and strap brands that work with Fitwell.