Section 2: Equipment
Conforming Clubs and Balls
All clubs and balls used in USGA championships must conform to the USGA Equipment Standards published by the USGA's Equipment Standards committee. The standards include:
- Conforming Drivers: driver heads must be on the published Conforming Driver Heads list maintained by the USGA
- Conforming Golf Balls: balls must be on the published Conforming Golf Balls list (the list is updated regularly; players are responsible for using a conforming ball model)
- Grooves: club grooves must conform to the post-2010 groove specifications
- Spring effect / MOI / dimension limits: all clubs subject to the published characteristic-time, MOI, club length, head size, and other USGA Equipment Standards limits
One-Ball Rule
USGA championships apply the One-Ball Rule: during a stipulated round, the player must use a ball of the same brand and model. The penalty for breach is, in stroke play, two strokes per hole at which any breach occurred (with a maximum penalty of four strokes per round). The rule is intended to prevent players from changing ball characteristics during a round to suit different conditions.
14-Club Limit
The 14-club limit (Rule 4.1b of the Rules of Golf) applies in full: a player may start a stipulated round with no more than 14 clubs and may not add a club during the round except in narrow exceptions. Breach is a stroke-play penalty of two strokes per hole at which the breach occurred (maximum four strokes per round).
Distance-Measuring Devices and Electronic Devices
Per the 2026 USGA Local Rules:
- Distance-measuring devices that measure distance only are permitted
- Devices that measure or display slope, wind, elevation, or other relevant conditions are NOT permitted during a stipulated round at USGA championships (the standard championship-level prohibition)
- Mobile phones are restricted: text messaging and phone calls are prohibited; specific app usage is permitted only in the narrow scope of distance-only measurement