The Mahle low-tension moly ring set specified for a 4.000" bore provides a matched piston ring kit for engines with that bore dimension. From Mahle OE, the moly ring pack is intended as a direct replacement during engine rebuilds or maintenance where a low-tension molybdenum-faced ring set is required to fit a 4.000-inch cylinder bore.
Mahle Rings Claimer Performance Low Tension 4.000 Bore Moly Ring Set