Charles Leven’s practice driver shows how far a golfer's practice swing would have hit a golf ball. To do this there is a mechanism located in the crown of the driver that operates on the principle of centrifugal force.  To demonstrate this, his club is shown twice in the first image.  I will explain: 

 When the driver is swung, the weight inside the head moves towards the toe. The harder the club is swung, the farther the weight moves. A ratchet device then locks the weight at the most distant position it attains.

A small triangular mark, visible in the top of the head, registers the weight’s movement against yardage measurements printed on the mechanism’s cover plate. The cover plate is open down the center so that the triangular mark, which moves underneath it, can be seen. Pushing a small button on the back of the head resets the mechanism and moves the indicator back to zero.

The cover plate on this Leven driver is marked “The ‘Leven’ Practice Driver \ Patent Applied For,” along with yardage measurements “0, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300.”

The mechanism in this club works well. As shown in one of the images, the auctioneer's practice swing moved the indicator to "125" yard mark. Another image shows the indicator mark at "0," the result of pushing the button on the back of the head to reset the indicator.  Working examples of a Levin driver are nigh unto nowhere, but this beautiful working example is one of the few that remain. 

With its 43" shaft and original leather-wrapped grip, the club represents a mechanical marvel in the world of antique golf clubs. Fine condition no issues - works. "ROD" stamped on toe.