Equipment Rules

This publication contains guidelines to help manufacturers, rules officials and other interested parties interpret the Rules relating to the design and manufacture of golf clubs and balls, as set forth in Appendices II and III of "The Rules of Golf."

Similar to the Rules, these guidelines will be continually reviewed, and modifications may be made in the future. The principles and philosophies expressed within this publication are held by both the United States Golf Association and R&A Rules Limited ("The R&A").








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Rule 5 — The Golf Ball


Rule 5-1 provides that the ball that a player uses must conform to the Rules and that the use of a ball which does not conform to the Rules will result in disqualification. However, the player would have to play a stroke with a non-conforming ball in order for the disqualification penalty to apply (see also Decision 5-1/3 in “Decisions on the Rules of Golf”).

The List of Conforming Golf Balls

Manufacturers may submit balls to the United States Golf Association and The R&A for testing. Twenty-four samples of each ball type (model) must be submitted to obtain a conformance ruling. If the samples conform to the Rules, they are entered onto the List of Conforming Golf Balls, which is updated on a monthly basis. The current list can be found on the USGA’s Web site at Full details of the golf ball submission procedure can be obtained from the USGA.

Ball types remain on the List for one year. However, random tests are carried out by the USGA and The R&A on selected balls to ensure that the ball characteristics remain the same. If a conformance issue is identified during random testing, the ball may be removed from the List.

Normally, only the Committees in charge of competitions involving expert players (at the state, regional and national level for amateurs, or at professional events) introduce a Condition of Competition requiring a player to use a ball included on the List of Conforming Golf Balls, the penalty for breach of the Condition being disqualification. However, if this Condition is not in place, it is assumed that a ball used by a player conforms unless there is strong evidence to the contrary (e.g., a player used a 1.62 inch diameter golf ball).

Foreign Material (Rule 5-2)

As with the club, the most important question to ask if confronted with a ball which has had something applied to it by the player is “why did the player apply it?” If the purpose of the application is to influence the movement of the ball, it would be prohibited.

Markings applied to the ball by the player (e.g., using a felt-tip pen) are not contrary to this Rule. Rules 6 5 and 12 2 encourage the player to put an identification mark on his ball to help ensure that he plays his own ball throughout the round. There are no regulations to limit what or how many markings can be applied to the ball by the player, provided its original markings can be discerned.


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The USGA and Chevron have committed to using the game of golf to encourage students in science, technology, engineering and math (STEM) disciplines. This commitment has led to the creation of extensive golf-focused STEM teaching tools, and has resulted in charitable contributions to support golf-related programs through Eagles for Education™

At U.S. Open Championships the Chevron STEM ZONE™ is an interactive experience highlighting the science and math behind the game of golf through a variety of hands-on exhibits and experiments.

The partnership has also produced educational materials such as the Science of Golf video series and a nationally-distributed newspaper insert which are provided to teachers as tools to enhance existing curriculum in schools. These lessons teach the science behind the USGA’s equipment testing, handicapping, and agronomy efforts.

For more interactive experiences featuring golf-focused STEM lessons, visit the partnership homepage.

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Rolex has been a longtime supporter of the USGA and salutes the sportsmanship and great traditions unique to the game. This support includes the Rules of Golf where Rolex has partnered with the USGA to ensure golfers understand and appreciate the game.

As the official timekeeper of the USGA and its championships, they also provide clocks throughout host sites for spectator convenience.

For more information on Rolex and their celebration of the game, visit the Rolex and Golf homepage.

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IBM has partnered with the USGA to bring the same technology, expertise, and innovation it provides to businesses all over the world to the USGA and golf's national championship.

IBM provides the information technology to develop and host the U.S. Open’s official website,, as well as the mobile apps and scoring systems for the three U.S. Open championships. These real-time technology solutions provide an enhanced experience for fans following the championship onsite and online.

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Lexus is committed to partnering with the USGA to deliver a best-in-class experience for the world’s best golfers by providing a fleet of courtesy luxury vehicles for all USGA Championships.

At each U.S. Open, Women’s Open and Senior Open, Lexus provides spectators with access to unique experiences ranging from the opportunity to have a picture taken with both the U.S. Open and U.S. Women’s Open trophies to autograph signings with legendary Lexus Golf Ambassadors in the Lexus Performance Drive Pavilion.

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Together, American Express and the USGA have been providing world-class service to golf fans since 2006. By creating interactive U.S. Open experiences both onsite and online, American Express enhances the USGA’s effort to make the game more accessible and enjoyable for fans.

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