Part Name: 3KC1 Piston Ring Kit Set OEM Number: 8-94411-568-1, 8944115681 Application: Fits 3KC1 Engine EX12K, EX12S, EX15S, EX15K, EX30UR Excavator Product Specifications: Piston Diameter: 74mm Pin Diameter: 21.0 x 66.5mm Ring Size (5-12121-031-0): 2.0 x 1.5 x 3.5mm This kit includes a complete set of piston rings and related components designed for standard 74mm piston applications in the specified excavator models.