1.  Field
This invention relates to golf swing practice aids, especially to devices producing audible feedback of wrist angle during a golf swing. 
2.  Prior Art
Various means for sensing and indicating the wrist angle, or constraining the wrist to a particular angle, for training in sports such as golf and bowling, have been used in the past.  However, an ideal combination of practicality, sensitivity, comfort, adjustability, and economy have not been achieved. 
U.S. Pat.  No.  2,831,196 (Scheiber) shows a golf glove with splints (14 and 15) in pockets oriented longitudinally across the back of the wrist.  The splints are tightened against the wrist so that cocking the wrist causes a discomfort that reminds the golfer not to cock the wrist too soon in the back-swing. 
U.S. Pat.  No.  2,064,603 (Harrison) shows an Audible Signal Device for use in golf and other sports.  It has a case the shape and size of a wrist watch, with a wrist band attached.  The case is strapped to any side of the wrist, and has a forward extending lever which contacts the hand adjacent the wrist for indicating bending of the wrist toward the case.  The lever depresses a spring steel clicker in the case to alert the user.  The timing is adjusted by replacing the lever with one of a different size, or by bending the lever. 
A device on the market as of this writing has an elongated spring steel clicker in a flexible envelope attached longitudinally across the back of the wrist by a strap around the wrist.  A retainer loop on the front end of the clicker can be placed around a finger of the hand.  In operation, the clicker presses against a location on the back of the hand and against a second location on the wrist.  These pressure points are not adjustable as to position.  Clicker timing is adjusted via the tension of the wrist strap.