A : width lug (do not measure the strap but the gap only you have between the watch
ears on both sides of the case),
B : width gap inside the buckle,
C : length of the long part (seize the length you would lke to order for your new strap),
D : length of the short part (seize the length you would like to order for your new strap),
E : * tongue buckle width (if you want to keep your OEM buckle),
F : * the between watch axes (length of your watchcase from pin to pin).