Wikipedia
Krap
The krap is Thai percussion instrument, which comes in three varieties.
The krap koo is made from two pieces of split bamboo, approximately 40 cm in length.
The krap puang is made from thin wood or brass, often consisting of a number of pieces tied with string. It is used in royal ceremonies.
The krap saepa is made from wood, like the ranat ek. It has a length of about 20 cm and a thickness of about 5 cm. The krap saepa is rectangular in shape, and is used in pairs.