Kobold armoursmiths have recently begun mass-producing suits of armour made from the organic hides of giant beetles. The smiths claim that this advance results from their own hard work and study, though it is widely believed that they were taught the basic secrets of chitin armourworking by the troglodytes.
Though less durable than dragonhide, chitin armour (also known as beetleback armour) has other advantages. Chitin is less restricting than metal, even though it weighs the same amount. The maximum Dexterity bonus of an armour or shield made of chitin is 1 greater than that of the same type of armour made from metal. Breastplates, half-plate armour, full plate armour and shields can be made from chitin. (Typically, the only kind of shield crafted from chitin is a tower shield, since most shields don’t have a maximum Dexterity bonus.)
A single giant beetle provides enough material to create a single breastplate or tower shield sized for a character of the same size category as the beetle (or two such items for a character two or more sizes smaller than the beetle). For example, a Large giant stag beetle has enough chitin to make either a breastplate or a tower shield sized for a Large character, or two such items for Medium or smaller characters. A suit of half-plate or full plate armour takes twice as much chitin, while a light shield or heavy shield takes half as much. (A chitin buckler can be made from the cast-off bits of any giant beetle.) The chitin from multiple giant beetles can be combined; a Small beetle counts as half of a Medium beetle, a Medium beetle as half of a Large beetle, and so forth.
Because chitin armour isn’t made from metal, druids can wear it without penalty. Armour and shields fashioned from chitin are always masterwork items; the masterwork cost is included in the prices given below. Chitin armour or shields cost double what masterwork armour of that type ordinarily costs, but take no longer to make than ordinary armour of that type.
Chitin armour has 10 hit points per inch of thickness and hardness 5.
Source: Races of the Dragon (Page 121)