Splint Mail +1

Splint Mail +1 is a piece of enchanted armour. When this armor is compared to Splint Mail, it offers an armor class that is one point lower and for only half the weight, which is 20 lbs. This piece of armor is not sold at any store, but four pieces at least of this armor can be found in buildings of Baldur's Gate, so it is available from chapter five.

One piece can be found in a locked chest in the headquarters of the Flaming Fist in the area where Duke Eltan can be found. Another piece can be found on the second floor of the Ducal Palace in a locked container. The others two sets can be found in house of the twins and one in the house of Degrodel in the northwest area of Baldur's Gate. The set in Degrodel's house can be stolen without problems after you complete his subquest.

In-game description
"Splint Mail is a varient of banded mail in which the metal strips are applied vertically to the backing of chain, leather, or cloth rather than horizontally as in bended mail. Since the human body does not swivel in mid-torso as much as it flexes back to front, splint mail is more restrictive in battle."