The Third-Arm Sash was a Shen Gong Wu that functioned as a third arm. It was first discovered in Paris, France by Jack Spicer and Wuya. However, Jack lost it to Clay in a showdown. When used with Clay Bailey's Earth element, the arm became a fist made of clay and slammed the ground. It was a requirement for the creation of Mala Mala Jong.
The Thirs-Arm Sash was a blue sash with three (or four) silver tassels at the end that served as the "fingers".
The Third-Arm Sash gave the user the ability to use it as a third, super-strong and durable hand. The "hand" was also extremely elastic, able to extent several meters away. When combined with Clay's earth element the arm became a fist made of clay, able to break rock, stone and wood.
It was first seen in Jack's possession in Paris, and was thought to have been found there. Jack later lost it in a showdown against Clay for the Fist of Tebigong. When Jack's robot, the Chameleon-Bot, disguised itself as Kimiko, it intentionally lost the Third-Arm Sash to Jack. It was later used to form Mala Mala Jong's right arm, and when it was defeated, the monks got it back. Jack later stole it in again, but the monks got it back when each monk had a showdown against their own worst fear. It was used by Raimundo's fear, a jellyfish-like monster. When Jack stole it again, the Wu was once again used to make Mala Mala Jong and acted as its right arm, as well as the arms of the rest of the Fearsome Four. The monks received it once again after defeating the Fearsome Four, and they have had it ever since.