Rubber goods. United States Government master specification for matting, rubber, for use around electrical apparatus or circuits not exceeding 3,000 volts to ground, Federal Specifications Board Specification 414, officially promulgated by Federal Specifications Board, May 22, 1926, for use of Departments and independent establishments of Government in purchase of rubber matting for use abound electrical apparatus or circuits not exceeding 3,000 volts to ground.