Ben Hogan once commented that he wished he "had two right hands", providing of course his left one arrived first. That's what the Key makes possible. It positions the right hand correctly, similarly to Hogan's, thus helping provide the delayed hit for greater distance and more consistent accuracy.
Correct right hand release, aided by the Key, also discourages both fat and thin shots with the irons. Even putting and chipping benefits as the right hand becomes correctly positioned. The Key is pre-bent to fit the wrist position of most hands. One of the Key's distinct advantages, however, is that it is malleable and can be adjusted to fit any adult hand. In addition it does not interfere with normal use of the fingers meaning the player can still grip the club properly while still minimizing any wrist movement.
Normally a right-handed golfer would purchase a right-handed 'The Key' to keep the right wrist bent. This, in effect, will also keep the left-wrist flat, however some players prefer to purchase a left-handed 'The Key', straighten it out and wear it on the back of the left wrist to keep it flat. This option works just as well although we targeting the source of the problem - the right wrist - is a better choice.