Abstract: A racquet system having a frame, an interchangeable string head, and optionally, a damper membrane to reduce vibration. The hoop-shaped frame head inner surface contains a channel, contoured to accept the outside surface of the damper membrane. The damper membrane is shaped to interfit between the string head and frame head. The string head possesses string holes for forming a high tension grid of strings. The string head is shaped to interfit within the frame head. The string head and damper membrane are locked in place in the frame head.

Abstract: A fingernail stimulating device including a housing adapted for holding in the palm of the hand, one or more vibrators contained within the housing for resiliently engaging the end and top surfaces of fingernails placed through a side opening in the housing, and drive means connected to the vibrators. For operation the drive means may obtain their power either from batteries contained within the housing or from an external power source. The device may also be provided with a thumbnail stimulator similar in construction to the fingernail stimulator.