Convert from wah [Thailand] to X unit

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.

Unit Definition (X unit)
The X-unit (symbol xu) is a unit of length formerly used to measure the wavelength of X-rays and gamma rays. The X-unit is approximately 1.0021×10-13 metre. Defined by the Swedish physicist Karl Manne Georg Siegbahn (1886-1978) in 1925, the X-unit could not at that time be measured directly; the definition was instead made in terms of the spacing between planes of the calcite crystals used in the measuring apparatus.