Apple Watch are sold in ten case sizes, and the straps are only compatible within two groups. Anyone who gets it wrong once knows how inconvenient it is to return a package. Here's an overview to simplify your choice.
Two size groups
| Group | Case sizes | Spigen straps labeled |
|---|---|---|
| Smaller | 38 / 40 / 41 / 42 mm (Series 10 and 11) | 42/41/40/38 mm |
| Larger | 44 / 45 / 46 / 49 mm (including Ultra) | 49/46/45/44 mm |
Note on 42 mm: older Series 1 to 3 in 42 mm belong to the larger group, new Series 10 and 11 in 42 mm belong to the smaller group. Therefore, always check the Compatibility dropdown with the list of models on the product page.
How to measure your wrist
Wrap a strip of paper around your wrist and measure the circumference. Spigen states a range for each strap, for example, 160 to 215 mm for the metal Modern Fit. Silicone straps are more tolerant, metal links are shortened by removing links, which for Modern Fit only requires the included tool.
Materials
- Modern Fit (316L stainless steel): for the office and evenings, weight around 60 g.
- Lite Fit (nylon with velcro): for sports, lightweight, quick-drying.
- Rugged Band (TPU): durable, matches the Rugged Armor Pro case.
When a watch case makes sense
Rugged Armor Pro is a strap and case in one: the watch case is surrounded by a TPU frame with a raised edge around the display. It's useful for sports, cycling, and work where the watch might hit obstacles. The buttons and rotating crown remain freely accessible, and charging works without removal.
