Smooth set of Blackwood bones: 7" long x 7/8" wide, with a slight curve. The thickness taperes over the length from 1/16" to 1/4". The dense hard Blackwood gives a clear tone when struck. Hold one between the thumb and index, or between the index and middle fingers, so the flat side is between the fingers and it curves toward you. This one should hang down along your inner wrist. This one is held so it does not swing freely. The second one is held between the middle and ring fingers with the flat side between the fingers and the convex curve facing the convex curve of the first bone. Let it hang down along your inner palm and swing freely. To play, shake your hand and swing your wrist. The bones will clap against each other in a variety of rhythms. Lots of fun.