From the NannyMUD documentation

LAST CHANGE

2001-10-06

RULES

NAME
        armour - rules on armours


DESCRIPTION
	Armours must have a type. Some types are allowed to have an
	armour class other than zero: armour, amulet, boot, cloak,
	glove, helmet, ring and shield.  Note the singular in all
	cases! There are limits on how good armours are allowed to
	be. As usual, rare specimens with drawbacks might be allowed
	to exceed the limits below, but be sure to get them approved.

	Type is the mandatory type for the item. The class is the
	value set with set_class(). The class determines the minimum
	weight and the approximate value of the item. Values of 200
	should be interpreted as 'at most 200' while higher values are
	allowed to vary with plus minus 30% .

	The table below specifies allowed weight and class for the
	different allowed armour types. Note that this table shows the
	BEST allowed numbers; it is allowed to have worse.

	If you have an armour with extra qualities/powers, you are NOT
	allowed to have the best weight and/or class on it.
	
	 Type     Class Weight Value     Type     Class Weight Value  
	+--------+-----+------+-------+ +--------+-----+------+-------+
	  armour   2     1      200       shield   1     1      200
	  armour   4     1      200       shield   2     2      200
	  armour   5     2      200       shield   3     4      200
	  armour   9     5      500       helmet   1     1      200
	  armour  12     9     1000       helmet   2     2      200
	  armour  15 *  12     3800       helmet   3     3      200
	  glove    1     1      200       boot     1     1      200
	  glove    2     1      200       boot     2     2      200
	  glove    3     2      200       boot     3     3      200
	  cloak    1     1      200       ring     1     1      200
	  cloak    2     2      200       ring     2     1      200
	  cloak    3     3      200       ring     3     1      200
	  amulet   1     1      200
	  amulet   2     2      200
	  amulet   3     2      300

	*: Exceedingly rare, typically AT MOST one per area.
	OTHER TYPES

	You can make armours with any type as long as they have class zero
	and no other purpose than decoration/feelings/drawbacks. Be careful
	when you do this, or we will end up with players wearing a helmet, a
	bowler, a cap and a top hat at the same time...


	MORE READING

	Read the doc on simple_armour and look at the examples in
	/examples/ for hints on how to create and customise your
	armours.