How to measure the mounting width?

Using a calliper or ruler, measure the exact distance between the watch lugs where the strap is attached. From the FIXING WIDTH AND BUCKLE TYPE list, select the appropriate size. The selected watch strap width must match the width between the watch lugs. The widths available in our store: 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 26 mm