Convert from X unit to arsheen [Russia]

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.

Unit Definition (arsheen [Russia])
The Arsheen, also called the Archin, Archine, Archinne, Arschine and Arshin. In the early 18th century, the Tsar Peter the Great issued a ukase redefining the traditional Russian units of length in terms of the English foot. The archin was made equal to 28 English inches, 71.12 centimeters or 16 Vershki.