Convert from millimicron to palmo [Spanish]

Unit Definition (millimicron)
A unit of metric measurement 1000 millimeters equal one meter, 10 millimeters equal one centimeter, about 25 millimeters is one inch.

Unit Definition (palmo [Spanish])
The palmo is a traditional unit of distance in Spain and Portugal. The traditional Spanish palmo equals 9 pulgadas or 1/4 vara: this is about 20.9 centimeters in Spain and a little more than that in Spanish Latin America. Under the metric system in Spain, the palmo is an informal unit equal to 20 centimeters. These units are based on the width of a person's outstretched hand, from the tip of the thumb to the tip of the little finger, a definition identical to that of the English span.