(RB25DE/T- B Type- w/Intake Retainer- Only Solid- 10.25mm Lift) Built for the (95-98) Nissan Skyline... At Tomei Powered, they have valve springs for many applications. Their R+D departments target was to develop valve springs with the best overall material and surface hardened finish for delivering the best performance results when needed. With many test prototypes they have the best final end product to deliver satisfaction and results. These were made for high RPM and high power tuned engines that are running high lift and big profile camshafts.