Brand New ProComp Set of 8 Zero Gap Moly High Performance Piston Rings, 4.060" Bore, Metric (Part #4640). These piston rings are designed to stand up to the rigors of racing and high performance street use while providing long lasting life. Features: Plasma-coated, barrel-shaped, ductile iron top rings that seal against blow-by when the piston rocks in its bore. Tapered secondary rings that seal against the oil control rings upper surface for excellent oil control. 3-piece oil rings with stainless steel expanders that provide accurate tension without the loss of any horsepower. Sold in sets of 8. Specs: Piston Bore Size: 4.060" Top Piston Ring Facing Material: Plasma Moly Top Piston Ring Material: Cast Iron Top Piston Ring Thickness: 1.5mm Middle Piston Ring Material: Cast Iron Middle Piston Ring Thickness: 1.5mm Oil Piston Ring Material: Stainless Steel Oil Piston Ring Thickness: 3 mm Quantity: Set of 8