French catheter scale

Charrière (CH) and ( Charr. ) refers to a measure of the medicine external diameter of cannulas and catheters. In the English -speaking world the size is simply referred to as French ( Fr). Charriere a corresponding third millimeter outside diameter. It was named after Joseph -Frédéric -Benoît Charrière.

The size of cannulas is also often expressed in gauge.