Your watch, now with micro-adjust.

Add half-hole micro-adjustment to your existing strap setup. No hardware swap required.

Available in 16 / 18 / 20 / 22mm Installs in under 2 minutes ⭐ 4.6 from 97 reviews

How It Works

  • 1. Slide the M4 onto your strap
  • 2. Reattach your existing buckle or deployant
  • 3. Adjust between two positions (3mm apart)

Will It Work For Me?

  • ✅ Tang buckles (spacers included)
  • ✅ Most spring-bar deployants
  • ✅ Leather, rubber & fabric straps
  • ❌ Omega-style deployants
  • ⚠️ Screw-attached deployants, chat with us below

Every M4 ships with a spring bar and spacer kit.

What Size Fitwell Should I Buy?

Use our easy Fitwell Size Finder to quickly determine your buckle size.

Step 1 — Calibrate your screen

Hold a standard credit card to your screen in portrait (vertical) orientation. Adjust the slider until the card image matches your card exactly, edge to edge.

Match all four edges of your physical card to this image

•••• •••• •••• 4291 FITWELL

85.6mm

Step 2 — Select your strap width

Each buckle is drawn to scale. Hold the end of your strap against the inner opening to find your exact size.

The inner gap of each buckle equals its labeled width, measured on your calibrated screen.

Your size:

Choose a product type below to see all options in your size.

Customers are saying

4.63 ★ (100)
Verified

Fitwell makes precision micro-adjust links: a universal micro-adjust link that adds half a hole of adjustment to your existing watch strap without swapping the buckle. It fits between your strap and its deployant clasp or pin buckle, so the closure you already own gets on-the-fly fit. Machined from 316L stainless steel and titanium, in 16, 18, 20, and 22mm.