The SwarShala Indian music software includes Khol and over 100 other perfectly sampled virtual Indian instruments.
The Khol is a terracotta drum used in northern and eastern India (Bengal, Manipur, …) for accompaniment of devotional music. It has a hollow body made of hardened earth or wood, with drum heads on both ends made of three layers of goat/cow skin. These drumheads are attached to the body by rice paste, special glue, and iron ore.
The left head is similar in size to Pakhawaj or Mridangam, but the right head is very small, giving the Khol a very high pitch.
This instrument is very common in Indian temples; for example, every Vishnu temple uses it during its rituals. It also forms an integral part of an accompaniment when medieval poets recited poems. A very popular Indian dance that employs this instrument is the Sangeet Nritya.