Hastings 3.917"/99.50 mm Bore +.040" Over Size, Single Cylinder Ring Set with 2.00 mm Top Ring, 1.50 mm Second Ring and a First Oil Ring is 4.00 mm.
This Hastings Single Cylinder Ring Set has a top ring manufactured from ductile iron with plasma moly ring surface treatment, a second ring manufactured from grey iron with phosphate ring surface treatment. The 1st oil control ring is manufactured of steel rail/stainless expansion with a chrome rail ring surface treatment.

Application Summary:

Year Make/Model
1970-1973 Nissan 240Z
1974 Nissan 260Z
Attributes
1st Oil Groove 4.00
1st Oil Ring Material STEEL RAIL/STAINLESS EXP
2nd Groove 1.50
2nd Ring Surface Treatment PHOSPHATE
Alternate Part Number 2M4532S.040
California Proposition 65 No
Engborein 3.917
Engboremetric 99.50
Hazardous Material Code N
Life Cycle Status Code Available to Order
NAFTA Preference Criterion Code B
SDR Required Flag N
Top Groove 2.00
Top Ring Surface Treatment PLASMA MOLY
GTIN 00075538284567