US Open using device that measures net tension

The U.S. Open represents a showcase for a tennis invention that measures net cord tension.

David Glass, an engineer from Knoxville, received a patent for his TNT Gauge system in November 2010. The device, about 7 inches long and 1 ¼ inches wide, goes on the anchor hook on the outside of a net post.

Glass, an amateur tennis player, believes his device can provide consistency in net tension.

He says Wimbledon is "notorious" for very loose nets while nets at the U.S. Open were so tight the ball could bounce very high or completely out of bounds. He says "there was an inconsistency in the game."

After experimenting with Glass' device on two outer courts last year, the U.S. Open is using it on all courts.