The Glong Tad is a large double-face drum to be beaten with sticks. The body of the drum is in cylindrical shape with a bulging central part. It is made of hard wood hollowed through to function as a sound box. The two faces of the drum are stretched over with cow hide or buffalo hide and fixed to the body of the drum with pins made of metal, ivory or animal bone, which are called “Sae Glong”. The sap from the lacquer tree is applied on the central part of each face to maintain the leather. A metal ring, called “Hoo Rawing” is attached into the middle of one side of the body for tying with rope to the stand when the drum is placed on the floor while played in the Pii Pat ensemble. Normally, two drums are used in the Pii Pat ensemble. The drum that produces high tone is called “Tua Poo” (male), while another drum that produces low tone in called “Tua Mia” (female).
         The Glong Tad has an important role when played together with the Tapone in a Pii Pat ensemble to accompany the Khon, Lakorn or Nang Yai performances since antiquity. It has been developed from one drum to three drums for suitability in various occasions.
         Besides, the Glong Tad was used as a signal drum, such as beaten at the temple drum tower to announce the lunch time for monks, or beaten at the city drum tower to mark the time of day, which was called “Glong Yam Pra Surisee”.