Hastings brand. A good grade piston ring for your A. One set does all 4 pistons. For the 3-ring type of piston. For the 1928-34 4-cyl. Hastings recommends a gap of .012" - .022" on the top and middle rings, and .010" - .050" on the oil rings, (which is different than the Ford manuals). U.S.A.