RSA = Roller Skating (Operators) Association
The Roller Skating Rink Operators Association was established in 1937 by a group of skating center owners to promote roller skating and establish good business practices for skating rinks. Known today as the Roller Skating Association International, they are a global trade association representing more than thousands of individuals from skating center owners and operators to teachers, coaches and judges of roller skating in artistic/roller hockey and speed skating, as well as manufacturers and suppliers of roller skating equipment.
Source; Ebay
Don in SoCal