WISECO REPLACEMENT RING SET.* XG type sets consist of Top Ring, Compression Ring, and Oil Ring.* Top Ring: Chrome-faced high temperature steel alloy.* Compression Ring: Taper-faced ductile iron.* Oil Ring: 3-piece low tension oil ring.* The ring type and bore size (in mm) is stamped on the dome of the piston.* Refer to this information to order the correct replacement rings.* Ring styles cannot be interchanged.* Please note: Only WISECO replacement ring sets may be used on WISECO pistons.