If this is your first time changing your watch straps, you need to determine your watch straps size!
There are some easy ways to know your size :

1. Lug Width
– Measure the distance between the inside of the lugs of the watch face in millimeters (mm) using a ruler.
– Do a quick google search for the lug width of your specific watch model. Example : “Panerai 000 lug width”
– Check the back side of your current watch strap to see if it has a size imprint shown in millimeters. Usually some OEM strap has this on the back.

2. Length
– Measure your wrist with a soft tape measure by wrapping it around your wrist at the exact area you wear your watch. Measure it in tight position.
– If you have an existing leather strap that fits your wrist well, measure the long side and short side length-wise separately in millimeters with a ruler to determine the length. Don’t include the buckle when measuring the short strap.

Here is our size chart :

4.5 – 5.0″ wrist (115 – 127mm) = 100/60mm
5.0 – 5.5″ wrist (127 – 140mm) = 110/60mm
5.5 – 6.0″ wrist (140 – 150mm) = 115/65mm
6.0 – 6.5′ wrist (150 – 164mm) = 120/70mm
6.6 – 7.0′ wrist (165 – 178mm) = 125/75mm
7.1 – 7.5″ wrist (179 – 190mm) = 130/80mm
7.6 – 8.0″ wrist (191 – 203mm) = 135/80mm
8.1 – 8.5″ wrist (204 – 216mm) = 140/85mm
8.6 – 9.0″ wrist (217 – 229mm) = 145/90mm