RING SET K261069 (Std.) 4 Rings fits DAVID BROWN Fits Case fits IHOne New Aftermarket Replacement Piston Ring Set for David Brown and Fits Case Fits Case IH Tractors This standard bore piston ring set (K261069) is a per cylinder engine rebuild component for David Brown and Fits Case Fits Case IH agricultural tractors and construction equipment. The set services the David Brown AD series diesel engines (AD3 49, AD3 55, AD4 49, AD4 55, AD4 55T, AD6 55T) and restores compression and ring seal in worn cylinders.