Convert from button measure to wah [Thailand]

Unit Definition (button measure)
The button measure is a unit of distance equal to 1/40 inch (0.635 millimeter), used to measure the thickness of buttons.

Unit Definition (wah [Thailand])
The wah is a traditional unit of distance in Thailand, now aligned with the metric system as exactly 2 meters (6.562 feet). This unit is the Thai version of the fathom. It is seen mostly in connection with the talangwah or square wah (4 square meters or 4.784 square yards), a common unit of area in Thailand.