W.W.G.S.
2019 R&A Rules of Golf
Click on the links in bold below for a full explanation of each rule
4 - Equipment
Use of Clubs Damaged During RoundA club damaged during a round can continue to be used, even if you damaged it in anger.
Replace a Club Damaged During RoundYou are not allowed to replace a damaged club during a round if you were responsible for the damage.
Use of Distance-Measuring DevicesThe use of DMDs is allowed unless a Local Rule has been adopted prohibiting their use.