Table tennis rackets normally have both sides covered with rubber on the striking surface. The international rules for the sport sets limitations to how this covering may be composed, and the ITTF has a system of approval for rubber products allowed in official competition. The List of Authorised Racket Coverings - abbreviated LARC - is a document maintained by the ITTF, listing all makes of coverings currently allowed. The list is freely available as a PDF document, and can be downloaded from the ITTF website. To get approval for a new type of rubber, the maker is required to submit samples to the ITTF for testing and approval, and also pay a regular fee to maintain the authorization of each type of rubber. Typically, coverings are removed from the list if the maker desists to pay the fee for that particular type, fails to submit samples when renewed testing is required, or if the rules change to exclude that particular rubber.
The LARC is published twice in a year by ITTF. The first without any alphabet after the years in and the second one with a B after the year . E.g. first will be 2017 and the second will be 2017B.