Convert from palmo [Texas] to millimeter

Unit Definition (palmo [Texas])
The palmo is a traditional unit of distance in Spain and Portugal. The traditional Spanish palmo equals 9 pulgadas or 1/4 vara. In Texas, 1/4 vara comes to 8 1/3 inches (21.17 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.

Unit Definition (millimeter)
The millimeter (or millimetre) is one of the most common metric units of distance. One millimeter is exactly one thousandth of a meter. The millimeter is also an engineering standard unit.