Buckler

Bucklers, also known as target shield, are the smallest shields available, usually made from wood or metal. They can be use by many classes, expect mages. These shields are available in three different colors, like the other three different shields. Target shields offer an armor class bonus of +1 and since it described by the game that these shield provide no protection to missile and slashing attacks, they provide -1 protection vs. slashing and missile to compensate for the armor class bonus. They all have a weight of 2 lbs. Bucklers are sold at Candlekeep Inn, Thunderhammer Smithy, Nashkel Store, Ulgoth's Beard Inn and many more stores that are selling weapons and armor.

In-game description
"A buckler, also known as a target shield, is a small round shield of wood or metal that fastens to the forearm. Because of it's size it is light and can be worn with very little restriction to movement."