diff --git a/src/fvr/geom.py b/src/fvr/geom.py
index 2de9dda..d32cfdb 100644
--- a/src/fvr/geom.py
+++ b/src/fvr/geom.py
@@ -2,6 +2,9 @@ from fvr.typing import FloatArray
 
 def area(vertices: FloatArray) -> float:
   r"""Determine the area of a simple polygon.
+
+  Args:
+    vertices: List of points, pair of x and y: "[[x1, y1], [x2, y2], ...]"
   
   Shoelace formula, Gauss's area formula, surveyor's formula
 
diff --git a/src/fvr/wire.py b/src/fvr/wire.py
new file mode 100644
index 0000000..48b3ef6
--- /dev/null
+++ b/src/fvr/wire.py
@@ -0,0 +1,41 @@
+import math
+
+class awg:
+  """AWG wire.
+  """
+  def __init__(self, number: int|str):
+    """Determine parameters for a given AWG wire size.
+
+    Args:
+      number: AWG wire size, also '00', '000', '0000'
+    """
+    self.number = number
+    self.num2int()
+
+  def num2int(self):
+    if isinstance(self.number, int):
+      self._number = self.number
+    elif self.number.isdigit():
+      if self.number in ['00', '000', '0000']:
+        self._number = 1 - len(self.number)
+      else:
+        self._number = int(self.number)
+    else:
+      raise ValueError
+
+  @property
+  def diameter(self):
+    """The diameter for a given AWG wire size in mm"""
+    return 0.127 * 92**((36-self._number)/39)
+
+  @property
+  def area(self):
+    """The area for a given AWG wire size in mm²"""
+    return math.pi/4*self.diameter**2
+
+  def __str__(self):
+    res = (
+      '%s' % self.number + ' AWG\n'
+      'A = %.4g' % self.area + ' mm²\n' +
+      'd = %.4g' % self.diameter + ' mm\n')
+    return res