How to Size Your Cut-to-Size (CTS) FKM Rubber Strap

November 16, 2025

Our premium FKM rubber straps are designed for you to switch up your Zenmaster look, allowing for versatility to always match your Zenmaster to your personal style. They’re comfortable, easy to size and made from premium FKM rubber, the highest quality rubber you can find.

Our straps are cut-to-size (CTS), meaning you can easily trim them to your exact wrist size yourself for a clean, perfect look, leaving no excess strap.

In this blog we are offering you a simple step-by-step guide to help you size your strap correctly and safely.

What you’ll need

Pin-pusher (included in the packaging)
Sharp knife or scissors
Measuring tape

Pro tips before you start

Visual: Minimalist text overlay on product background.

Cut sections evenly from both sides.
Use sharp scissors or a knife for clean edges.
Cut conservatively. You can always cut another section, but you can’t add one back!
The clasp has two micro-adjustment holes to ensure the best possible fit

Step 1: Prepare your workspace

Grab a soft, flat and uncluttered surface to work on, like a desk mat. Have a small ruler or measuring tape ready, along with your pin-pusher and a steady hand.

Step 2: Understand the strap layout

Flip the strap over. On the inner side, you’ll see a series of evenly spaced cutting lines. Each line marks a section that can be safely removed to shorten the strap.

⚠️ Important:
Only cut along the designated lines. Cutting anywhere else could damage the internal holes that hold the spring bars, which means that section can’t be used anymore.

Step 3: Detach from the clasp

Use the included pin-pusher to gently press down on the spring bar that connects the strap to the clasp. This will release one side of the strap and should be enough to detach the strap from the clasp.

Tip: Push straight into the hole, don’t twist or force it. A light push should release the spring bar. Be careful not to lose the spring bar!

Step 4: Check the sizing table

Before making any cuts, check the sizing table to see how many sections we recommend cutting. Since this is just an estimation, we advise you to first cut one section less than what the sizing table says. That way you can test the fit before committing to cutting another section.

Some like a looser fit, some like it as tight as possible! Find out what works for you before you cut off another section.

It’s best to cut one section at a time from each side to maintain symmetry.

Start conservatively. You can always remove more, but you can’t add it back.

Wrist size (cm)	Wrist size (inch)	Top sections to cut	Bottom sections to cut
14.0	5.51	10	9
14.5	5.71	9	9
15.0	5.91	9	8
15.5	6.10	8	8
16.0	6.30	8	7
16.5	6.50	7	7
17.0	6.69	7	6
17.5	6.89	6	6
18.0	7.09	6	5
18.5	7.28	5	5
19.0	7.48	5	4
19.5	7.68	4	4
20.0	7.87	4	3
20.5	8.07	3	3
21.0	8.27	3	2
21.5	8.46	2	2
22.0	8.66	2	1
22.5	8.86	1	1
23.0	9.06	1	0

Step 5: Cut carefully along the guides

Using a sharp utility knife or scissors, carefully cut along the cutting line on the inside of the strap.

✅ Cut cleanly and straight across the marked line.
❌ Don’t cut through any of the spring bar holes between sections, because if you do, that section can no longer attach to the clasp.

Repeat on the other side of the strap.

Step 6: Reattach the strap to the clasp

Once you’ve cut both sides evenly, slide the spring bar through the new end section of the strap and secure it back into the clasp. Make sure to attach the strap attached to the side of the clasp with the logo to the bottom of the case!

You should feel or hear a small “click” when it locks in place. After reattaching it, gently tug on the strap to ensure it’s seated properly.