This sturdy 18 note movement is the most widely used type of musical movement in craft and hobby projects. The mechanism on this movement is encased in a removable white plastic shell that measures 1" L x 2" W x 1- 7/8" H. When fully wound, it plays approximately 2-1/2 minutes and has a nice range of tones. Our music boxes are 18 note mechanisms. This means that it only plays 18 notes of the desired tune, not the entire song. When fully wound, it will play at its fastest speed and gradually slow down. This may be faster than the tune is usually played and is typical of standard music boxes. It winds from the bottom and comes with a gold-colored 3/4"L winding key.