You’ve found the perfect rubber, leather, or silicone strap on BluShark Straps, but then you hit the dropdown menu: Small Strap? Large Strap? Ultra?

With Apple releasing new Series, SE, and Ultra models every year, the case sizes (measured in millimeters) keep changing. It can be confusing to know which strap fits your specific wrist computer.

Whether you are rocking an original Series 1 or the latest Apple Watch Ultra, this guide will help you identify your model and select the exact size you need for a seamless fit.

Step 1: Which Apple Watch Do You Have?

Before you pick a strap size, you need to know exactly which watch you own. If you tossed the box years ago, don't worry—the answer is on your wrist.

Check the Back of the Case

Remove your watch from your wrist and look at the engraving on the back of the metal case (around the sensors). Apple explicitly engraves two pieces of information here:

1. The Model: (e.g., "Series 7," "SE," or "Ultra")
2. The Size: (e.g., "41mm" or "45mm")

Once you have that millimeter number, finding your BluShark strap size is easy.

Step 2: The BluShark Sizing System

At BluShark, we simplify the confusing array of Apple sizes into three easy categories based on the connector width.

⚠️ Important Note on 42mm Watches: If you have an older Series 1, 2, or 3 (42mm), you need a Large Strap. If you have the newer Series 10 or 11 (42mm), you need the Small Strap.

Step 3: The Master Size Chart

Locate your watch model below to see exactly which BluShark strap size to add to your cart.

How to Order on BluShark Straps

Now that you have identified your size, purchasing is simple:

1. Browse our collection and click on the strap style you love.
2. On the product page, look for the Size dropdown menu.
3. Select Small, Large, or Ultra based on the chart above.
4. Choose your hardware finish (buckle and adapter color) to match your watch case (Silver, Space Black, Gold, etc.).

Our adapters are designed for a precision fit, ensuring your new strap clicks into place just like the original.

Ready to upgrade your wrist game?