The Rain-Bathing Cloth (Vassikasataka)
It is traditionally similar in use to a pha khao ma (a multipurpose Thai cloth). The Buddha permitted monks to use it as an eighth cloth, in addition to the standard three piece robe set (the triple robe / trai jiwon). The rain-bathing cloth, also called the vassikasataka, is a cloth that monks use to change into when bathing especially during the rainy season so they can maintain modesty and keep their bodies covered while washing. Because it is associated with the Rains Retreat(Vassa), there is a tradition of offering rain-bathing cloths before the start of the retreat. This custom is said to originate from a story from the Buddha’s time in which Visakha, the great laywoman, offered such cloth to the community of monks.